I've been writing Elixir on-and-off since 2017 for personal projects and since 2024 professionally, at a big tech company.
The two experiences couldn't be more different. While I loved the great development speed for my personal projects, where I am writing more code than reading it,
joining an existing project needs the opposite, reading more code than writing it.
And I can only repeat what many people say, dynamic typing makes this so much more difficult. For most code changes, I am not 100% certain which code paths are affected without digging a lot through the code base. I've introduced bugs which would have been caught with static typing.
So in my conclusion, I'm bullish on gleam, but also on other (static) languages embracing the cooperative green-thread/actor model of concurrency like Kotlin (with JVM's virtual threads).
(On another note, I personally also dislike Phoenix LiveView and the general tendency of focusing on ambiguous concepts like Phoenix Context's and other Domain Driven Design stuff)
I worked a year or so at an Elixir shop, and this mirrors my experience. I had to navigate to call sites to understand what I was being passed and type hints were not sufficient. Dynamic typing fails larger orgs/teams/codebases.
Fun to develop and solo administer. Small teams with a well known codebase can do amazing things. I work at orgs with multiple teams and new hires who don't know the codebase yet.
There are type hints for function parameters. With some care and guards, Dialyzer can be somewhat helpful.
What actually drove me nuts was absence of guards and meaningful static analysis on return values. Even in my small but nontrivial personal codebase I had to debug mysterious data mismatches after every refactor. I ended up with a monad-like value checking before abandoning Elixir for my compiler.
Fully agree with this based on similar experiences. IME most devs hired without previous Elixir/Phoenix experience don’t end up liking the tech stack very much, even though they become productive quite quickly and don’t struggle too much with Elixir. A lot of Elixir/Phoenix fans make the mistake of thinking that everyone is going to love it as much as they do once they get up to speed.
Isn't there some kind of optional typing in Elixir?
What you're describing are the same uncertainties I've used to have writing PHP a long time ago, but since using optional types and PHPStan checker, it kind of serves as a compiler pass that raises those issues. The benefit being that I still can be lazy and not type out a program when I prototype the problem on my first pass.
>Isn't there some kind of optional typing in Elixir?
It’s in the works and recent versions of the compiler already catch some type errors at compile time, but it’s nothing remotely close to what you get from Typescript, or from any statically typed language like Go, Rust, Java, etc.
The referenced post is from 2020, and nubank still posts clojure content and sponsors the big clojure conference, so I’d be shocked if they were dropping clojure.
Their tech stack is probably enormous, it wouldn’t surprise me if they’re using both for different things
Also the referenced post is about them acquiring plataformatec, not about using elixir. Jose Valim (the creator of elixir) left plataformatec after the nubank acquisition in order to continue developing elixir, I've never heard of nubank using elixir, afaik they're solidly a clojure shop with no plans on changing.
it's just an internal I/O-bound project, where BEAM concurrency makes lots of sense. Grown from an engineer's side project as it was useful and working well, not a company-wide effort to bet on Elixir
Am I the only one who never tried Elixir just because it has no strict typing?
Seems very hard for me to go back to a language with dynamic typing. Maybe I'm just wrong and I should give it a try.
It is alleviated quite a bit bz its pattern matching capabilities combined with the "let it crash" ethos.
They have a success typing system (which isn't very good) and are working on a fuller system (which isn't very mature).
If typing is the only thing keeping you out, have a look at Gleam.
Having worked with Elixir professionally for the last six years now, it is a very mature platform, very performant and offers many things that are hard in other languages right out of the box.
I see this phrase around a lot and I wish I could understand it better, having not worked with Erlang and only a teeny tiny bit with Elixir.
If I ship a feature that has a type error on some code path and it errors in production, I've now shipped a bug to my customer who was relying on that code path.
How is "let it crash" helpful to my customer who now needs to wait for the issue to be noticed, resolved, a fix deployed, etc.?
>How is "let it crash" helpful to my customer who now needs to wait for the issue to be noticed, resolved, a fix deployed, etc.?
Let it crash is more about autorestarting and less about type bugs. If you have a predictable bug in your codepath that always breaks something, it just means you never tested it and restarting will not fix it. But this kind of straightforward easy to reproduce bugs are also easy to test the hell out of.
But if you have a weird bug in a finite state machine that gets itself into a corner, but can be restarted -- "let it crash" helps you out.
Consider hot reload -- a field exists in a new version of a record, but doesn't exist in a old one. You can write a migration in gen server to take care of it, but if you didn't and it errored out, it's not the end of the world, it will restart and the problem will go away.
I wonder what production monitoring is like for that. Does Elixir have a good monitoring platform like NewRelic for tracking the state of these processes?
The core of a properly built, resilient/robust system is that you have compartmentalized code into different small erlang processes. They work together to solve a problem. A bug in one is isolated to that particular process and can't take the whole system down. Rather, the rest of the system detects the problem, then restarts the faulty process.
The reason this is a sound strategy is that in larger systems, there will be bugs. And some of those bugs will have to do with concurrency. This means a retry is very likely to solve the bug if it only occurs relatively rarely. In a sense, it's the observation that it is easier to detect a concurrency bug than it is to fix it. Any larger system is safe because there's this onion-layered protection approach in place so a single error won't always become fatal to your system.
It's not really about types. It's about concurrency and also distribution. Type systems help eradicate bugs, but it's a different class of bugs those systems tend to be great at mitigating.
However, if you do ship a bug to a customer, it's often the case you don't have to fix said bug right away, because it doesn't let the rest of the application crash, so no other customer is affected by this. And you can wait until the weekend is over in many cases. Then triage the worst bugs top-down when you have time to do so.
In addition to the other fine replies, it helps to remember that Erlang/BEAM, and by extension Elixir, comes from the telephony world. If something crashes in that world, you'd far rather terminate a phone call spuriously than bring the whole system down. (And in the 1990s, when the main alternative was C, and not just C as it may be today but 1990s C specifically, that was a reasonable concern.) Erlang is optimized for a world where that's a reasonable response to a failure. I've also used it in a context where a system makes a persistent connection up to a controller, and if either side crashes they automatically reconnect. "Let it crash" is a reasonable response to a lot of issues that can arise.
The farther you get from that being an issue, the less useful the "let it crash" philosophy becomes, e.g., if I hit "bold" in my word processor and it fails for some reason, "let it crash" is probably not going to be all that helpful overall.
I have seen systems that "should" have been failures in the field be held together by Erlang's restart methodology. We still had to fix the bugs, but it bought us time to do it and prevented the bad deployments from being immediate problems. But it doesn't apply to everything equally by any means.
Okay but “static typing avoids the crash to begin with”, is what everybody from the static typing world is thinking reading all these very long responses that don’t address this very basic idea.
I like to measure languages by "what do I miss when I leave them".
I used Erlang professionally for about 5-6 years.
I have not missed "let it crash".
It's an interesting idea that should be grappled with, but Erlang users have this tendency to very badly strawman their opposition and spout their propaganda like it's still 2005 and the rest of the world has just been twiddling their thumbs, gormlessly ramming into brick walls as they scale up and are just flabbergasted about how to handle the problems of scale, when in fact, to a first approximation all of the large systems in the world that are reliable are also not written in BEAM. There are other solutions to the problem. Strong types are a big component of how I deal with this in my current code, yes. It's not 100% a solution, but then, I can have both anyhow so I generally do.
I was just providing context. When trying to understand BEAM it is always helpful to have in the back of your head that it was written for telephony, with all that implies.
"Crashing is loud" below is a phrase to combine with "remote error recovery" from the link above. Erlang/OTP wants application structure that is peculiar to it, and makes that structure feel ergonomic.
> If I ship a feature that has a type error on some code path ... How is "let it crash" helpful to my customer?
The crash can be confined to the feature instead of taking down the entire app or corrupting its state. With a well-designed supervision structure, you can also provide feedback that makes the error report easier to solve.
However, while a type error in some feature path is a place that makes type annotations make sense, type annotations can only capture a limited set of invariants. Stronger type systems encode more complex invariants, but have a cost. "Let it crash" means bringing a supervisor with simple behavior (usually restart) or human into the loop when you leave the happy path.
> "Let it crash" means bringing a supervisor with simple behavior (usually restart) or human into the loop when you leave the happy path.
If a "human" has to enter the loop when a crash occurs, this limits the kind of system you can write.
I had to work on a system where a gen server was responding to requests from a machine, sent frequently (not high frequency, but a few times per second.)
If for some reason the client misbehaves, or behaves properly but happens to use a code path that has a type error, the only option given by "let it crash" was to, well... crash the actor, restart the actor, then receive the same message again, crash the actor, restart the actor, etc... and eventually you crash the supervisor, which restarts and receives the same message, etc...
Crashing is loud. You will get crashes in your logs. And you can let it happen because those crashes won't disrupt anything else - that's what the message passing gets you.
So sure, the code with the error won't work (it wouldn't work in any language - you can make an error in all of them), but you will get a nice, full stack trace and the other processes in your VM won't be impacted at all. You won't bring down the service with a crash. Sometimes this is undesirable - you could deploy a service where the only endpoint that functions is the health check - but generally people don't do that.
I feel like the other comments I see here, are not expressing the deeper point, and you're asking to really understand something, so that's what you care about? So I'm sorry to pile on when you've got like a dozen good answers, but.
Let It Crash refers to a sort of middle ground between returning an error code and throwing an exception. It does not directly address your customer's need, and you are right that they are facing a bug.
So if you were to use Golang with Let It Crash ethos, say, you would write a lot of functions with the same template: they take an ID and a channel, they defer a call to recover from panics, and on panic or success they send a {pid int, success bool, error interface {}} to the channel -- and these are always ever run as goroutines.
Because this is how you write everything, you have some goroutines that supervise other goroutines. For example, auto-restart this other goroutine, with exponential backoff. But also the default is to panic every error rather than endless "if err != nil return nil, err" statements. You trust that you are always in the middle of such a supervisor tree and someone has already thought about what to do to handle uncaught errors. Because supervision trees is just the style of program that you write. Say you lose your connection to the database, it goes down for maintenance or something. Well the connection pool for the database was a separate go routine thread in your application, that thread is now in CrashLoopBackoff. But your application doesn't crash. Say it powers an HTTP server, while the database is down, it responds to any requests that do not use the database just fine, and returns HTTP 500 on all the requests that do use the database. Why? Because your HTTP library, allocates a new goroutine for every request it handles, and when those panic it by default doesn't retry and closes the connection with HTTP 500. Similarly for your broken codepath, it 500s the particular requests that x.(X) something that can't be asserted as an X, we log the error, but all other requests are peachy keen, we didn't panic the whole server.
Now that is different from the first thing that your parent commenter said to you, which is that the default idiom is to do something like this:
type Message {
MessageType string
Args interface{}
Caller chan<- Message
}
// ...
msg := <-myMailbox
switclMessageType {
case "allocate":
toAllocate := args.(int)
if allocated[toAllocate
msg.Caller <- Message{"fail", fmt.Errorf(...), my mailbox}
} else {
// Save this somewhere, then
msg.Caller <- Message{"ok", , my mailbox}
}
}
With a bit of discipline, this emulates Haskell algebraic data types which can give you a sort of runtime guarantee that bad code looks bad (imagine switching on an enum `case TypeFoo`: foo := arg.(Foo)`, if you put something wrong in there it is very easy to spot during code review because it's a very formulaic format)
So the idea is that your type assertions don't crash the program, and they are usually correct because you send everything like a sum type.
Thank you for this very detailed explanation! I think between this and the other very welcome replies, I think I have discovered what I didn't understand: that "let it crash" addresses a different set of problems than static types, but that a dynamic type system can still be helpful in avoiding type errors in the first place, if it leads you to design data structures in a certain way.
Thanks for your answer!
I already checked Gleam several times and it looks amazing. The ecosystem just doesn't feel mature enough for me yet. But I can't wait for it to grow.
True. There is inter-op with both Elixir and Erlang, but thsts like early TypeScript.
If you're at all interested, I'd suggest doing the basic and OTP tutorials on the Elixir Website. Takes about two hours. Seeing what's included and how it works is probably the strongest sails pitch.
There is also pattern matching and guard clauses so you can write something like:
def add(a, b) when is_integer(a) and is_integer(b), do: a + b
def add(_, _), do: :error
It’s up to personal preference and the exact context if you want a fall through case like this. Could also have it raise an error if that is preferred. Not including the fallback case will cause an error if the conditions aren’t met for values passed to the function.
Writing typespecs (+ guards) feels really outdated and a drag, especially in a language that wants you to write a lot of functions.
It reminds of the not-missed phpspec, in a worst way because at least with PHP the IDE was mostly writing it itself and you didn't need to add the function name to them (easily missed when copy/pasting).
True but by using guards + pattern matching structs you can approximate type hinting, but it feels cumbersome and more of a workaround than a real solution.
I'm of the opinion that Erlang/Elixir are terrible for repeat tasks like a standard CRUD server over a SQL database. Because yes, it IS cumbersome! Behaviors and type hints only get so far, and it is exhaustingly slow to sit with epgsql in the REPL to figure out what a query actually returns.
I find them much better suited for specific tasks where there is little overlap or repetition.
I’d recommend it. I used to think I needed statically typed languages to write sound code, but after enough time with Elixir (10 years professionally and going) I really don’t believe that to be true… A huge portion of my change of heart is due to Elixir (and Erlang) being functional and only having a handful of types:
There are a few others but they are generally special cases of the ones above. Having so few data types tends to make it much more obvious what you’re working with and what operations are available. Additionally, because behavior is completely separate from data it’s infinitely easier to know what you can and can’t do with a given value.
Ruby being dynamic drove me insane at times, but Elixir/Erlang being dynamic has been a boon to productivity and quality of life. I recently had to write some TypeScript and was losing my mind fighting the compiler, even though I knew at runtime everything would be fine. Eventually I slathered enough “any” on to make the burning stop… But! That’s something I haven’t had to do in years, and it was 100% due to type system chicanery and not preventing a bug or making the underlying code more sound.
There are still some occasions where having some static typing would be nice— but they’re pretty rare and often only for things that are extremely critical or expensive to fix. And IMHO even in those cases, Elixir’s clarity and lack of (implicit) state generally make up for it.
Here's my take as TS dev. You just never learned to use types in the first place where there is very little ambiguity on any types anywhere because there is close to no any's used. Sounds like you guys get high and mighty on your tunnel-visioned copium—I mean I used to write JS for god's sake and thought it was okay. And I remember when I first tried TS felt annoyingly hampered by having to actually use interfaces properly.
Sure, the nature of Elixir probably makes it easier but I find little joy in dynamic whack-a-mole and mental gymnastics to infer types instead of fricking actually being able to see them immediately.
I could go commando in TS as well and switch to JS and JSDoc, leaving everything gradually typed and probably be fine but I'd feel terribly sorry for anyone else reading that code afterwards. It'd be especially silly since I can now just infer my auto-generated Postgres zod schemas with little effort. Moreover, a good type system basically eliminates typing-related bugs which you guys apparently still have.
So please, don't over-generalize just because you think you got it figured out.
Lmao. This has to be the funniest comment I’ve ever read on here. I can assure you, the only copium being huffed is by you, mate. I have written Scala, Swift, Java, and more (including TypeScript). I have zero trouble with type systems, but I have wasted enough time fighting them for little real world benefit. In Elixir, and this is the best part, I don’t fight type bugs. You probably do because type erasure means you can still have them if someone has mistyped something or shit on something at runtime— the joys of JavaScript.
It sounds like you’re really trying to justify something and that’s great for you. I’m really happy for you. Keep it up. May you soar where no junior dev has dared to soar before. God speed.
Hah. Sure buddy, Mr. Sr Dev. Sorry if I offended you and your vast experience. Without types there definitely aren't type bugs, I grant you that, and JVM languages are quite different to TS. I don't know if your argument on type erasure is any better than advocating for dynamic typing but it definitely happens when you just start throwing anys.
And look, I'm first to admit that TS type system isn't perfect (and it can cause some devs to go overboard) but I have read my share of Python scripts that were read-only from the minute they were born.
It sounds like you’re really trying to justify something and that’s great for you. I’m really happy for you. Keep it up. May you soar where no junior dev has dared to soar before. God speed.
And please, your condescension just sounds insecurity to me. It's highly amusing though that you try to play me down as a silly junior dev, I'm quite satisfied that my original assessment was correct.
There's also tooling like dialyzer, and a good LSP catches a lot too. The language itself has some characteristics that catch errors too, like pattern matching and guard clauses.
With all that said, I'm still very keen for static typing. In the data world we mostly start with Python without mypy, and it's pretty hard to go back.
Type systems in this space seem to take a long time and never quite reach completeness. At least that's the experience I've taken away from occasionally glancing at Erlang's Dialyzer project every now and again which I don't think has ever reached any semblance of the maturity of something like TypeScript.
But pattern matching in Erlang does do a lot of the heavy lifting in terms of keeping the variable space limited per unit of code which tends to reduce nesting and amount of code to ingest to understand the behavior you care about at any moment.
Generally I find static typing to be overrated, even more so with elixir due to pattern matching and immutability. I think elixir’s set-theoretic types will be a nice addition and will provide some compile-time safety checks without needing to explicitly define types for everything. It remains to be seen how far they’ll take this approach.
Biggest benefit of typing in TS is just autocomplete that knows to filter down suggestions to field name of the object type before the dot. That and constants without typos. That, exhaustive maps and interface implementations are really good to not forget things that have to be done outside of the currently open file.
really you wind up making only a handful of type errors that make it into prod.
there are other things that contribute to this like pretty universal conventions on function names matching expected outputs and argument ordering.
it does suck hard when library authors fail to observe those conventions, or when llms try to pipe values into erlang functions, and yes, it WOULD be nice for the compiler to catch these but you'll usually catch those pretty quickly. you're writing tests (not for the specific reason of catching type errors), right? right?
I tried it for a job interview, and it was awful - because of no static typing. I spent most of my time tracking down dumb type errors, compounded by various language footguns (I can't remember exactly, but I think for example making a typo on a field name in a for loop condition is treated as "condition false" and so the for loop just doesn't do anything, no error).
It seems like the Elixir/Erlang community is aware of this, as is Ruby, but it's a rather large hole they have to dig themselves out of and I didn't feel particularly safe using the tools today.
I've heard a lot of good things about the Erlang runtime and I did really like Elixir's pipe operator, so it was unfortunate.
You can also peek inside objects and check for types and values of nested properties. In other languages you’d need to create composite types or even duplicate or extend types. In Elixir, all that is for free. I see that as much more powerful than types.
Elixir is a strongly typed language (as opposed to a weakly typed language like JavaScript or Perl). You cannot, for example, do `"4" - 1` in Elixir. Dynamic vs static typing is a mostly orthogonal scale, where Elixir is (mostly) dynamically typed.
There are some very sharp Computer Scientists who believe static typing is unnecessary. Joe Armstrong (co-designer of Erlang) once said: "a type system wouldn't save your system if it were to get hit by lightning, but fault tolerance would"
I've never had a system crash from a lightning strike, fault-tolerant or otherwise. I have had systems crash from null pointer errors though, and fault-tolerance did nothing to fix that except turn a crash into a crashloop.
I have the same attitude toward overly permissive type systems that I do toward the lack of memory safety in C: People sometimes say, "if you do it right then it isn't a problem," but since it objectively IS a problem in practice, I would rather use the tool that eliminates that problem entirely than deal with the clean-up when someone inevitably "does it wrong."
We had a cluster of servers, dynamically scaling up and down in response to load, and one day started seeing errors where an enum string field had an impossible value. Imagine the field is supposed to be "FOO" or "BAR" but one day in the logs you start seeing "FOO", "BAR", "GOO", and "CAR". Impossible. "GOO" and "CAR" did not exist in the code, nothing manipulated these strings, yet there they were.
Long story short, a particular machine that joined the cluster that morning had some kind of CPU or memory flaw that flipped a bit sometimes. Our Elixir server was fine because we were matching on valid values. Imagine a typed language compiler that makes assumptions about things that "can't" happen because the code says it can't... yet it does.
I am not sure I want the system to continue operating in that scenario. You have corrupted hardware that could be trashing other records. What if it is flipping bits on financial transactions?
It's likely Armstrong conflated the two there because a significant part of the fault tolerance of Erlang comes from the loose coupling via message passing between components, which in no small part is tied to the dynamic typing. It's a Postel's law thing, being generous in what you accept and strict about you send.
Elixir's seamless pattern matching paradigm, IMO, largely negates the need for strict typing. If you write your function signatures to only accept data of the type / shape you need (which you are incentivized to do because it lets you unpack your data for easy processing), then you can write code just for the pretty path, where things are as expected, and do some generic coverage of the invalid state, where things aren't, rather than the norm in software development of "I covered all the individual failure states I could think of". This generic failure mode handling, too, greatly benefits from dynamic typing, since in my failure state, I by definition don't know exactly what the structure of my inputs are.
Yep, I have written and maintained several large scale applications In elixir and live the computation model.
However,elixir depreately needs proper types. IMHO the needs for types are in no means negated by pattern matching, and I also see hints at why you would say so.
> If you write your function signatures...
The point of types is worry less refactoring.
If you work at a place where you can define the arhicture for the entire lifecycle of the application without ever needing to Refactor, then sign me up! I want to work there.
Well, the people behind elixir seems to have accepted that typing is necessary.
I see this story on an on: some hacker makes a language, they hate types because they want to express themselves. The languages gets traction. Now enterprise application and applications with several devs use it and typing gets essential - types will then gradually be added.
sure part of the decision is that you can't really soundly type (in a developer sanity preserving way) across a cluster that runs multiple versions of software (which is a real use case that the authors absolutely needed to support as part of the core business). but they let dialyzer in to the core so it's not like the team was actively hostile to typing.
Okay? But "the features you need would have taken effort to implement, so we didn't implement them" is not a very good sales pitch when you're trying to convince me to use your tool to do my job.
Any tool that justifies the choice not to implement an important and highly-requested feature with "effort is a finite resource" alone is not viable for serious development work. It's not prioritizing, it's a refusal to prioritize.
Seems a bit strange to posit fault tolerance as an alternative to a type system. Personally, I view type systems as a bonus to DX more than something strictly designed to prevent errors
It's in line with the erlang philosophy of letting things crash trivially and restart instantly. Due to the universal immutability, starting a new process from a given state in Erlang/Elixir is nearly instantaneous and has extremely little overhead as they are not OS threads, they are BEAM VM threads.
LOL. This only makes sense if you can know all the ways your code will fail... which you cannot.
Erlang/Elixir's approach is to simply say, "It's gonna fail no matter how many precautions we take, so let's optimize for recovery."
Turns out, this works fantastically in both cellphone signaling, which is where OTP originated, as well as with webserving, where it is perfectly suited.
whether that matters or not depends on whether the logic error occurs because of a rare combination of events or as a result of a certain state and whether that state remains after recovery. if there is for example a logic error that causes the app to crash after say 10 minutes of runtime, or eg. at a certain message size, then a recovery will reset the runtime and it will work again. it will of course invariably fail again after another 10 minutes or when the same message is resent, because it is a logic error, and logic dictates that the error won't go away no matter how often you restart, but it will work in the meantime.
in other words, any error that doesn't occur right at start can be recovered from at least for all those operations that do not depend on that error being fixed.
This sound like a wild and very contrived argument.
Both because that memory leaks are normal is types languages - and does usually not matter in most serious applications - and because this class of errors is usually not what types catch.
Types have value when you 1) refactor and 2) have multiple people working on a code base.
The error you see when you don't have types is something like a BadArityError.
It doesn't prevent the error, but it also won't take down your server when malicious users (or just lots of normal users) start to bang on that input with the problem, and your non-BEAM VM pool starts to run out of available preloaded stacks... You get a new Erlang process in well under a millisecond on modern hardware
It WILL log the error, with a stacktrace, so you have that going for you
Note that even with typing, you cannot avoid all runtime errors
Also note that this tech was first battle-tested on cellphone networks, which are stellar on the reliability front
Nope, getting a TypeError on "1"+2 is not being "punished". That's way better than getting malformed data that you weren't expecting which keeps the system "working" until an error happens somewhere else, later, where it's more confusing.
OpenTelemetry.js did this. Being written in typescript they wrongly believed they didn’t need to check the data type for user-supplied numbers. Yeah so my production data started having dropouts because somewhere we incremented by “2” instead of 2, and then OTLP choked on 100% of the data from that process because one stat out of thousands was not to its liking and had a three thousand digit ‘number’ in it.
I never did track down the last spot where we screwed that up. This was a system we shifted from statsd, so the offending callers were either working by accident or only killing some data points for one stat and nobody noticed.
So then OpenTelemetry.js had to start sanitizing its inputs and not assuming the compiler should catch it. I still think it odd that something called “.js” was actually “.ts” under the hood.
how so? most dynamically typed languages are also strongly typed. that includes python, ruby, common lisp, smalltalk... if it was the worst option, this would not be the case.
sure, but when the majority of popular languages use that paradigm then it surely can't be the worst option either. what is it that makes it a bad combination?
At this point I'm reaching into the low percentages. I think it's pretty clear that Strongly + Statically typed languages are massively over-represented on the list.
Both Strongly and Weakly Dynamically typed languages are similarly represented.
Note: I'm open to editing the comment to move languages from and to various categories. I haven't used many of them, so correct me if I'm wrong.
smalltalk and common lisp don't qualify as popular languages
not anymore. they were very popular in the industry at one point. very few other languages have so many independent implementations as smalltalk and lisp. a testament to their wide spread use in the past.
that doesn't make sense. typescript is javascript with types, it can't be both strong and weak at the same time.
but i believe we have a different definition of weak. just because javascript, php and perl have some implicit type conversions doesn't make them weakly typed. i believe it takes more than that. (in particular that you can't tell the type by looking at a value, and that you can use a value as one or another type without any conversion at all)
C is weakly typed, it was always a major criticism, C++ too i think (less sure about that).
once you correct for that you will notice that all languages in the strong and static category are less than 30 years old and many are much younger. (java being the oldest. but there are older ones like pike which is also strong and static and goes back to 1991)
the strong and dynamic category goes back at least a decade more. (if you include smalltalk and lisp)
what this does show is that static typing has experienced a renaissance in the last two decades, and also the worst is really using any form of weak typing.
i still don't get what makes strong and dynamic a bad combination, other than it's bad because it is not static.
I mean, if you define weak like that, then yeah. But also, what languages are you left with? Assembly? Then again, it does fit with your definition of popular being popular 45 years ago. Tbh, I'm not sure if smalltalk was ever even popular. It was certainly influential, but popular?
I know that there are discussion about what strong vs weak even means, but I think most people would place the weak distinction way above yours on a possible weak-strong spectrum.
C can certainly be argued to be weak. My understanding is that it's mostly due to pointers (and void* especially). C++ is much better in this regard. I mostly just did not want to add a Weak + Static category just for one language.
Well, now that you've defined Strong to also include all of the languages I consider Weak, then yeah, no issues at all.
definitions are hard. but i am mostly concerned to make sure we are talking about the same thing, regardless of what that thing is called. i do accept and agree that javascript, php and perl may be considered weaker than python or ruby. but to which degree may be a matter of taste. to me they are still strongly typed for the most part. (and let's not get into the definition of static, that's another can of worms)
but the interesting question is really the one posed at the beginning. what makes strong but dynamic a bad combination?
i think we agree that weak is bad. implicit type conversions like 1+"2" range from the annoying to problematic and dangerous. if we eliminate weak that only leaves strong and static vs strong and dynamic.
i agree that strong and static is better in most cases, type declarations help, and pike the language i use the most myself which is somewhere between python and go, has powerful types that are a joy to work with, but for comparison in typescript types come across as more annoying (in part because they are somewhat optional, and because they get lost at runtime, so they don't help as much as in truly typed languages) but strong and dynamic has shown to be a solid combination, especially with python and ruby. so i don't feel the combination is as bad as you seem to suggest.
> smalltalk and common lisp don't qualify as popular languages.
Sure, Smalltalk isn't, but Lisp is a different story. In this context I assume we all mean to say "Lisp" and not "Common Lisp" specifically.
Lisp (as the entire family of PLs) is quite massively popular.
Standard rankings have major blind spots for Lisp measurement, they miss things like, for example, Emacs Lisp is everywhere. There's tons of Elisp on GitHub alone, and let me remind you, it's not a "general-purpose" language, its sole function is to be used to configure a text editor and there's mind-boggling amount of it out there. AutoLISP is heavily used in CAD/engineering but rarely discussed online. Many Lisp codebases are proprietary/internal. Also, dialect fragmentation artificially deflates numbers when measured separately - many rankings consider them different languages.
If you count all Lisp dialects together and include: Emacs Lisp codebases, AutoLISP scripts in engineering, Research/academic usage, Embedded Lisps in applications, Clojure on JVM and other platforms - babashka scripts, Flutter apps, Clojurescript web apps, etc;
...Lisp would likely rank much higher than typical surveys suggest - possibly in the top ten by actual lines of code in active use.
Yes you are. First of all there isn't such a thing as "strict typing", types are either static/dynamic and/or strong/weak. I suppose you meant Elixir has no static types. It is however a strongly typed language.
And just like it usually happens, static typing enthusiasts often miss several key insights when confronting dynamically typed languages like Clojure or Elixir (which was inspired by ideas implemented in Clojure).
It's not simply "white" and "black", just like everything else in the natural world.
You have to address:
- Runtime flexibility vs. compile-time safety trade-offs — like most things, things have a price to it, nothing is free.
- Different error handling philosophies. Sometimes, designing systems that gracefully handle and recover from runtime failures makes far more resilient software.
- Expressiveness benefits. Dynamic typing often enables more concise, polymorphic code.
- Testing culture differences. Dynamic languages often foster stronger testing practices as comprehensive test suites often provide confidence comparable to and even exceeding static type checking.
- Metaprogramming power. Macros and runtime introspection enable powerful abstractions that can be difficult in statically typed languages.
- Gradual typing possibilities. There are things you can do in Clojure spec that are far more difficult to achieve even in systems like Liquid Haskell or other advanced static type systems.
The bottom line: There are only two absolutely guaranteed ways to build bug-free, resilient, maintainable software. Two. And they are not static vs. dynamic typing. Two ways. Thing is - we humans have yet to discover either of those two.
You act like OP has never experienced dynamic type programming.
They clearly said they "can't go back to" it, meaning they've experienced both, are aware of the trade-offs, and have decided they prefer static types.
> Gradual typing possibilities. There are things you can do in Clojure spec that are far more difficult to achieve even in systems like Liquid Haskell or other advanced static type systems.
That's great for clojure and python and PHP, but we're not talking about them.
You act as if I said anything about anyone's experience. "they prefer static types" can mean a whole lot of things - there's type inference, soundness, turing-completeness, type classes, GADTs, higher-kinded types, dependent types, gradual typing, structural vs nominal typing, variance annotations, type-level programming, refinement types, linear types, effect systems, row polymorphism, and countless other dimensions along which type systems vary in their expressiveness, guarantees, and ergonomics.
Dynamic typing also varies - there's type introspection, runtime type modification aka monkey patching, different type checking strategies - duck typing & protocol checking, lazy & eager, contracts, guards and pattern matching; object models for single & multiple dispatch, method resolution order, delegation & inheritance, mixins, traits, inheritance chains, metaprogramming: reflection, code generation, proxies, metacircular evaluation, homoiconicity; there are memory and performance strategies: JIT, inline caching, hidden classes/maps; there are error handling ways, interoperability - FFI type marshaling, type hinting, etc. etc.
Like I said already - things aren't that simple, there isn't "yes" or "no" answer to this. "Preferring" only static typing or choosing solely dynamic typing is like insisting on using only a hammer or only a screwdriver to build a house. Different tasks call for different tools, and skilled developers know when to reach for each one. Static typing gives you the safety net and blueprints for large-scale construction, while dynamic typing offers the flexibility to quickly prototype and adapt on the fly. The best builders keep both in their toolbox and choose based on what they're building, not ideology.
In that sense, the OP is wrong - you can't judge pretty much any programming language solely based on one specific aspect of that PL, one has to try the "holistic" experience and decide if that PL is good for them, for their team and for the project(s) they're building.
Runtime flexibility is not restricted to dynamically typed languages, it just happens to be less available in some of the popular statically typed languages.
Error handling, expressiveness, testing culture, meta-programming and gradual typing have nothing to do with static vs dynamic typing.
The main "advantage" of dynamically typed languages is that you can start writing code now and not thing about it too much. Then you discover all the problems at runtime...forever.
Statically typed languages force you to think about what you are doing in advance a lot more which can help you avoid some structural issues. Then when you do refactor computer helps you find all the places where you need to change things.
Dynamically typed languages force you to write more tests that are not required in statically typed languages and that might prompt you to write other tests but if also increases the chance you just give up when you start refactoring.
Finally, after some time has passed and few updates have been applied to the language and libraries, you may not have a working project anymore. With statically typed languages you can usually find and fix all the compile errors and have the fully working project again. With dynamically typed languages, you will never know until you explore every line of code, which will usually happen at runtime and on the client computer.
i see things like that written almost on the daily but i've never seen it come to pass.
this is anecdotal but i've worked professionally in ruby and clojure and it was a pretty good experience. java/kotlin/scala made me wish i could go back to dynamic land...
these days i'm in a rust shop but i keep clojure for all my scripts/small programs needs, one day i intend to go back to some kind of lisp full time though.
Sure you're right on most of this, but allow me a slight pushback here. I am sorry, I am inclined to use Clojure/Lisp in my examples, but only because of its recency in my toolbelt, I could probably come up with similar Elexir examples, but I lack intimate familiarity with it.
- Dynamic languages can harbor bugs that only surface in production, sometimes in rarely-executed code paths, yes. However, some dynamically typed languages do offer various tools to mitigate that. For example, take Clojurescript - dynamically/strongly typed language and let's compare it with Typescript. Type safety of compiled Typescript completely evaporates at runtime - type annotations are gone, leaving you open to potential type mismatches at API boundaries. There's no protection against other JS code that doesn't respect your types. In comparison, Clojurescript retains its strong typing guarantees at runtime.
This is why many TS projects end up adding runtime validation libraries (like Zod or io-ts) to get back some of that runtime safety - essentially manually adding what CLJS provides more naturally.
If you add Malli or Spec to that, then you can express constraints that would make Typescript's type system look primitive - simple things like "The end-date must be after start-date" would make you write some boilerplate - in CLjS it's a simple two-liner.
- Static type systems absolutely shine for refactoring assistance, that's true. However, structural editing in Lisp is a powerful refactoring tool that offers different advantages than static typing. I'm sorry once again for changing the goalposts - I just can't speak specifically for Elixir on this point. Structural editing guarantees syntactic correctness, gives you semantic-preserving transformations, allows fearless large-scale restructuring. You can even easily write refactoring functions that manipulate your codebase programmatically.
- Yes, static typing does encourage (or require) more deliberate API design and data modeling early on, which can prevent architectural mistakes. On the other hand many dynamically typed systems allow you to prototype and build much more rapidly.
- Long-term maintenance, sure, I'll give a point to statically typed systems here, but honestly, some dynamically typed languages are really, really good in that aspect. Not every single dynamic language is doomed to "write once, debug forever" characterization. Emacs is a great example - some code in it is from 1980s and it still runs perfectly today - there's almost legendary backward compatibility.
Pragmatically speaking, from my long-term experience of writing code in various programming languages, the outcome often depends not on technical things but cultural factors. A team working with an incredibly flexible and sophisticated static type system can sometimes create horrifically complex, unmaintainable codebases and the opposite is equally true. There's just not enough irrefutable proof either way for granting any tactical or strategic advantage in a general sense. And I'm afraid there will never be any and we'll all be doomed to succumb to endless debates on this topic.
> The bottom line: There are only two absolutely guaranteed ways to build bug-free, resilient, maintainable software. Two. And they are not static vs. dynamic typing. Two ways. Thing is - we humans have yet to discover either of those two.
That's true but some languages don't let you ship code to prod that multiplies files by 9, or that subtracts squids from apricots
> that multiplies files by 9, or that subtracts squids from apricots
I don't understand why when someone mentions the word "dynamic", programmers automatically think javascript, php, bash or awk. Some dynamically typed PLs have advanced type systems. Please stop fetishizing over one-time 'uncaught NPE in production' PTSD and acting as if refusing to use a statically typed PL means we're all gonna die.
A funny thing is I once had a type bug while coding elixir, that bash or perl would've prevented, but rust or haskell wouldn't have caught. I forgot to convert some strings to numbers and sorted them, so they were wrongly sorted by string order rather than numerical order.
In haskell (typeclasses), rust (traits), and elixir comparison is polymorphic so code you write intending to work on numbers will run but give a wrong output when passed strings. In perl and bash < is just numeric comparison, you need to use a different operator to compare strings.
In the case of comparison elixir is more polymorphic than even python and ruby, as at least in those languages if you do 3 < "a" you get a runtime error, but in general elixir is less polymorphic, ie + just works on numbers, not also on strings and lists and Dates and other objects like python or js.
I also experienced more type errors in clojure compared to common lisp, as clojure code is much more generic by default. Of course noone would want to code in rust without traits, obviously there are tradeoffs here, as you're one of the minority in this thread recognizing. There is one axis where the more bugs a type system can catch the less expressive and generic code can be. Then another axis where advanced type systems with stuff like GADT can type check some expressive code, but at the cost of increasing complexity. You can spend a lot more time trying to understand a codebase doing advanced typesystem stuff than it would take to just fix the occasional runtime error without it.
A lot of people in this thread are promoting gleam as if its strictly better than elixir because statically typed, when that just means they chose a different set of tradeoffs. Gleam can never have a web framework like Phoenix and Ash in elixir, as they've rejected metaprogramming and even traits/typeclasses.
>>> open('foo') * 3
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for *: '_io.TextIOWrapper' and 'int'
You have to go to some length to get Python to mix types so badly.
Well, yes, Python can sure feel pretty fucking awkward from both perspectives. It started as fully dynamic, then added type hints, but that's not the main problem with it, in my opinion, the problem that you're still passing around opaque objects, not transparent data.
Compare it with Clojure (and to certain extent Elixir as well). From their view, static typing often feels like wearing a suit of armor to do yoga - it protects against the wrong things while making the important movements harder.
- Most bugs aren't type errors - they're logic errors
- Data is just data - maps, vectors, sets - not opaque objects
- You can literally see your data structure: {:name "Alice" :age 30}
- The interesting constraints (like "end-date > start-date") are semantic, not structural and most static type systems excel at structural checking but struggle with semantic rules - e.g., "Is this user authorized to perform this action?" is nearly impossible to verify with static type systems.
What static types typically struggle with:
- Business rules and invariants
- Relationships between values
- Runtime-dependent constraints
- The actual "correctness" that matters
Static type systems end up creating complex type hierarchies to model what Clojure does with simple predicates. You need dependent types or refinement types to express what clojure.spec handles naturally.
Elixir also uses transparent data structures - maps, tuples, lists, and structs are just maps. It has powerful pattern matching machinery over type hierarchies - you match on shape, not class. Elixir thinks in terms of messages between processes and type safety matters less when processes are isolated.
Python's type hints do help with IDE support and catching basic errors, yet, they don't help with the semantic constraints that matter. They add ceremony without data transparency. You still need runtime validation for real invariants.
So Python gets some static analysis benefits but never gains a truly powerful type system like Haskell's, while also never getting "it's just data" simplicity. So yes, in that sense, Python kinda gets "meh" from both camps.
I'm not sure what you're saying, but just in case if you're implying that choosing to use something like Clojure or Elixir adds "unnecessary layer of problems" just because they are not statically typed, let me remind you that "simplicity" is basically Clojure's middle-name. Rich Hickey made a seminal talk on simplicity, https://www.youtube.com/watch?v=SxdOUGdseq4 it's quite eye-opening and isn't really about Clojure. Every programmer should watch it, perhaps even multiple times throughout different stages of their career progression.
I don’t imply anything. I state (pun very much intended).
I cannot consider seriously anybody who thinks that programmer convenience and maintainability are different things on any level. And focusing on one doesn’t need the other.
Also this speech is academic blabla. I understand it, but there is a reason why he had to build a completely new vocabulary… because it’s not simple and easy at all. And there is a reason why there is exactly zero examples in almost the whole speech.
Because I can give you a very, very good example to contradict the whole speech: NAND gate.
Also you can code in Haskell basically with the same logic as in imperative languages (I used Clojure rarely, so I cannot say the same). So the “simplicity” is there only if you want to. But that’s true also the other way around: you can have the same “simplicity” in languages where mutability is the default. I agree that you should do immutability by default, but it’s stupid to enforce it. And he said the same thing, just it was a half sentence, because it contradicts everything what he preached: there are cases when his simplicity toolkit is the worse option.
Ruthless immutability causes less readable and maintainable code in many cases. And I state it, and I can give you an example right away (not like Hickey did): constructing complex data.
Also every time when somebody comes up with ORM and how bad it is, I just realize that they are bad coders. Yes, a lot of people don’t know how to use them. But just because it allows you to do bad things, doesn’t mean that it’s bad. You can say the same thing about everything after all. Every high level languages are slower than code in Assembly. Does that mean that every high level languages are OMG, and we should avoid them? Obviously not. You need to know when to touch lower layers directly. This is especially funny because there is a thread about that part on Reddit, because he used some vocabulary which is basically non existent, and the thread is a clear example of that people don’t even know what’s the problem with it. It’s a common knowledge that it’s bad, and they don’t know even why. For example, whoever fuck up a query through ORM, would fuck up the same way just with different syntax, like with a loop, because they clearly don’t know databases, and they definitely don’t even heard about normal forms.
And yes I state it again, using flexible type systems add unnecessary layer of problems. I also like that he mentioned Haskell, because it makes it clear, that his speech is completely orthogonal to the discussion here.
> Over time you will probably feel drawn to both, for different reasons
I agree 100%. At first I liked C# and Java types, but then I moved to Python and I was happy. Learning some Typescript pulled me back into the static typing camp, yet then I discovered Clojure it revealed to me how needlessly cumbersome and almost impractical TS type system felt to me in comparison. Experimenting with Haskell and looking into Rust gave me a different perspective once again. If there's a lesson I've learned, it's that my preferences at any point in life are just that - preferences that seldom represent universal truths, particularly when no definitive, unambiguous answer even exists.
That's quite the list of languages. If you're interested in types I would suggest also looking into F#. Shouldn't be tricky for someone who has already experienced C# and is open to different approaches to programming. For me F# was a revelation into what programming language typing can do for the developer.
I do know and like F#, and just like the other commenter I think I personally prefer it over some Haskell's ways. F# was my first FP language, I was so excited about it, but it was a hard sell back then to my team of charpers, so I sneaked it in by writing tests in it for an otherwise altogether C# codebase.
Too sad that the dotnet world largely still operates in csharpland and F# unfairly gets ignored even within dotnet community. I never have found a team where F# is preferred over other options, and I'd absolutely love to see what it's like. Unfortunately, F#'s hiring story is far worse than other less popular languages and even if there is anything, you most likely end up supporting other projects in C#, and honestly, even though it's a fine language by many measures, I see C# as "past experience" that I personally am not too eager to try again and do it as my daily job.
I really like the way F# (and presumably ocaml) do typing, it truly feels like the best of both worlds. Rarely do you need to actually write a type anywhere, and when you do it's because otherwise there might have been a runtime error.
I think a lot of people feel repulsed by dynamic typing for the same reason I used to: they wrote a lot of JS, and now they write a lot of TS. The experience of working in a JS codebase vs working in a (well-typed and maintained) TS codebase is a wide, wide gulf. I love working in TS, and I absolutely despise working in JS.
For a while I extrapolated my experience to mean “static typing is awesome and dynamic typing is horrible”, but then I started learning clojure, and my opinions have changed a lot.
There are a ton of things that make a codebase nice to work with. I think static typing raises the quality floor significantly, but it isn’t a requirement. Some other things that contribute to a good experience are
- good tests, obviously. Especially property based tests using stuff like test.check
- lack of bad tests. At work we have a very well-typed codebase, but the tests are horrible. 100 lines of mocks per 20 lines of logic. They’re brittle and don’t catch any real bugs.
- a repl!!
- other developers and managers who actually care about quality
All four of these examples seem pretty easy to find in the clojure world. Most people don’t learn clojure just to get a job, which is maybe a hidden feature of building your company with a niche language.
At the same time, I recognize that most of those examples are “skill issues”. Static typing does a good job of erasing certain skill issues. Which is great, because none of us are perfect all the time!
Exactly this. When speaking about static or dynamic type systems, you can't discuss them in isolation, you need to specify because the holistic experience of types in JS, Python, Clojure, Elixir, Haskell, Rust, etc. will differ, sometimes drastically. Leaning too much to any side is perilous; it may create a false narrative in your head about what types fundamentally mean and how they should be used.
Camping too long on either side may create wrong assumptions like that all/most problems are type problems; make you conflate implementation with concepts and make you miss the real tradeoffs; you'd start ignoring context and scale.
Static types aren't always about "safety vs. flexibility" - sometimes they're about tooling, refactoring confidence, or documentation. Dynamic types aren't always about "rapid prototyping" - sometimes they enable architectural patterns that are genuinely difficult to express statically.
One really needs to see how Rust's ownership system or Haskell's type inference offers completely different experiences, or how Clojure's emphasis on immutability changes the dynamic typing game entirely.
I wouldn’t say that static types remove the need for unit tests… but they do significantly reduce that need.
Static types and unit tests are not equivalent either. A static type check is a proof that the code is constructed in a valid way. Unit tests only verify certain input-output combinations.
I liked the article, but I found it a bit strange that it presented pure functions as a feature of Elixir rather than as a general good practice. Surely there's nothing particularly unique about Elixir in this regard compared to other languages?
> But honestly, I’ve always felt like this objection was overblown. I’ve got nothing against static typing; some of my best friends use statically-typed programming languages.
If you're trying to hot swap a function for a version with a different type signature, how was the new code going to run successfully anyway? Unless the type signature changes aren't reflecting the runtime behaviour changes?
I mean, lots of extremely talented and successful engineers, e.g., DHH, think strict typing is actually a negative. I think if you think strict typing is an absolute disqualifier, you should steelman the opposing side.
His "argument" for strict typing on the Lex Fridman podcast was also that it's mostly if you have "hundreds or (of?) thousands of engineers collaborating", which "strictly" puts his opinion in the bin in my case. I have absolutely, positively become more productive as a single developer due to strict typing. Parsing various kinds of binary data was enough to convince me. A.k.a. each to their own. On the whole, Elixir and BEAM seem really cool though, and there's work being done on typing, as well as the new Gleam language.
Note: I've not yet done any serious web-development, mostly command line tools, which I realise is not DHH's main focus.
I tried both and I respect different opinions about this. I feel like TS' type system makes me crazy because it's going too far. But no typing makes me anxious. I guess there is a sweet spot to find for me personally.
Anxious about what? What's your issue with dynamic typing?
Thorough tests of the behavior of your system (which should be done whether the language is dynamic or not) catch the vast, vast majority of type errors. "More runtime errors" in a well designed codebase don't mean errors for the user - it means tests catch them
Seriously.. the secret to writing great dynamic code is getting very good at testing
I come from a PHP and Python background. I can see how progressive addition of types has changed the way we deal with code. Working on a big old project without types is not even possible for me anymore. Refactoring things with types is already such a tedious task. Without it it's barely possible.
The thing is most useful for me about types is it serves as forced documentation. I look at function signature with types and know what kinds of values it accepts and what it returns.
For sure. The biggest advantages of static types I see is the better tooling + faster feedback for type errors. They're advantaegs but not that big of a deal and they're equal to the tradeoffs you're making to where it doesn't matter much
I see dynamic codebases being written differently though. We all know those tradeoffs - so conventions pop up to deal with them. A method that ends in a ? in ruby - like user.admin? - always returns a boolean. You get better at naming to make types clearer
I definitely miss the perfect automated refactorings though
I knew TS's type system went too far when I saw the 8 queens problem solved in just the type system, not the actual language. Me, I just want to get stuff done, not fight my type system.
And that was even before someone wrote DOOM in TS's type system.
It combines the "opinionated" aspects of ruby and rails and the power of erlang. The BEAM is like no other runtime and is incredibly fun to work with and powerful once you get how to use genservers and supervision trees.
We use Elixir for Mocha, and my one issue with it (I disagree with OP on this) is that live-view is not better than React for writing consumer grade frontends. I wish Phoenix took a much stronger integration with React approach, that would finalize it as the top choice for a web stack.
My current project is using React Native (for native and web) and getting GraphQL setup was initially a pain, but having React and GraphQL subscriptions gives me enough of the "live" functionality, but without having to worry about connection issues. With gql-tada, I get fully typed experience on the front-end too.
Yeah it’d be nice if they had a mix task to include your js frontend of choice and it “just worked”. Many have used inertia with success. I’m taking a different approach and pairing svelte with Phoenix channels.
Yes, it’s always a surprise to me that, given how great Elixir is, it didn’t take over backend development. It seems so much better suited to doing something similar to microservices without a lot of the overhead you’d think people would love it. It always seems that fads win and projects with extremely tight concepts remain niche.
While Elixir is my current favorite language to hack in, it is very alien and downright hostile to integrating with existing systems. For example, relational database support was postgres focused for a long time (to the exclusion even of SQLite and continued inability to talk to Oracle). Then you have articles like https://dashbit.co/blog/you-may-not-need-redis-with-elixir pushing ETS over Redis. While it's a valid argument, it's not adoption-friendly.
Clojure brings about half the novelty of Elixir, runs on the JVM and still struggles to replace Java.
Pretty sure there has been BEAM connectivity for Oracle for at least five years. SQLite3 is one of the defaults in Phoenix and have been for a long time. I do mix phx.new curious_idea --database=sqlite3 at least once a week, it's a sub-minute effort to a mostly generated base for a prototype (with OK auth/user management) I can just throw on a VPS and show someone.
If you want an in memory store without interfacing over HTTP, that is less foreign than ETS, try Duckdbex. Mix.install or add to mix.exs, then it's two lines and you get a connection to an ephemeral database with a SQL interface. Can probably do the same with SQLite but I've never done it. If your needs are simple you can just boot a GenServer with a K-V structure as state.
Pattern matching, the capture operator and functional programming style are the really "hostile" parts, in my experience.
One thing the author didn't mention is how incredibly polished the primary ecosystem of documentation, standard library, and tooling is. The Elixir standard library is incredibly consistent in order to support Elixir's piping operator, such that the first argument will basically always be the information you want passed from the function before it. In comparison, I frequently have to check the docs to confirm argument order on any lesser-used function in Python, Javascript, or C#. Then there's the fact that the second-layer of standard library, the OTP inherited from Erlang, which is expansive to the point of containing most things you'd want to do on a server. The documentation, in turn, is the gold standard that I (typically negatively) compare all other language docs to. It's organized, discoverable, and covers not just the "what" but the "How" and "Why" exceptionally well, not just at the function level, but the module layer as well. Frankly, only MDN comes close. All combined, it's just an incredibly productive language.
Hi! I recently tried to get into Elixir as an antidote to an acute javascript-fatigue...
To my surprise this there isn't really a good mobile story to build mobile apps for both Android and iOS with it, although it looks like it could be a great option for quick turnaround mobile apps with a web- or native frontend...
I know that there is something being worked on, eg. LiveView native: https://native.live/ , but that seems to target two entirely different frontend frameworks, one for each platform...
I started using capacitor as a wrapper for a HTML frontend, but I think I might potentially run into trouble when I'd try to move into production builds...
I think there's some space for research and maybe some nice starter packs / tutorials there... Because I think it is a big and pretty relevant market for browser-based apps, which Elixir seems to be very well suited to!
I'm grateful for any additional pointers, peace out! :)
This language and its upsides (that come from the VM) really are not for application development in this manner. I'm sure you can make it work somehow but its like using a tank to get groceries. Reliability, scalability, aren't concepts relevant to apps on mobile phones. If an app crashes to the homescreen thats fine, if your entire service goes down that's another. Would be fun if someone could prove me super wrong here but if you want to learn Erlang/Elixir/Gleam or anything BEAM I'd pick a backend project.
Uh, yeah, it's primarily a backend language, with any frontend stuff being either a thin layer or experimental, AFAICT. OTOH, doing a more traditional backend-heavy web app might be just the thing for JS fatigue. :)
I second the "9. What You Don’t Need to Worry About with Elixir" ; and indeed I would advice to _ignore_ some things that look like standards (kubenertes, docker, etc...) and embrace BEAM / OLTP / hot reloading, etc...
I've seen a world where we tried to ship an elixir app "as if it was a go microservice" - it does not work, does not help, and you loose a lot.
Also, I wish the author had addressed the static typing. This was my biggest pet peeve when working on a non trivial app for 5 years (Mistakes were made because actors are not familiar, and fixing those mistakes was hard because of a lack of static typing.) I wonder how the situation has changed lately with the introduction of _some_ type checking.
I've been using Elixir for about a year on a side project and I've been enjoying it more than any other backend I've used (Node, Rails and C#). I recently discovered Ash and I feel like after that initial learning curve my productivity (and code quality) has improved quite a bit.
I wish Elixir had more mindshare beside just LiveView and "real time" type functionality. Even building a GraphQL/JSON endpoint without real-time requirements, the functional nature (no side effects), pattern matching and ruby inspired syntax makes writing plain old JSON controllers a joy.
While Elixir might not have a package for every use case under the sun, the low level primitives are there.
Yes, the learning curve is a extremely high. It took a few false starts over time, but after the "Ash book" came out, I gave it a more serious try and it finally started to click for me.
I think it helped that at the time I was trying to build some pretty advanced filtering functionality using Ecto and was having a pretty tough time. While searching for solutions I saw a few mentions of Ash and that it could solve the problem out of the box.
After a few days of experiments, I found that it was able to do the filtering I wanted out of the box and was even more functional than what I was trying to build.
For reference, I was trying to add some tagging functionality to a resource and I wanted to be able to filter by that tag, including multiple tags. Can I do that in Ecto? Of course, but Ash provided that out of the box after modeling the resource.
I guess, but you'll be writing a _lot_ of code yourself, that might be hard to maintain and can become brittle overtime as requirements evolve.
As an example, I wanted to add support for adding tags to a resource, and support filtering for the resource by the tag, and I wanted to be able to do this filtering both through Elixir functions as well as GraphQL.
Can I do this with Ecto? Absolutely, but I'd have to build it all myself.
With Ash, I created a `Tag` and `Tagging` resource, adding a `many_to_many` block on my resource, marked it as public. Then I added the `AshGraphql.Resource` extension to my `Tag` resource, marked it as filterable and I was done.
Now I can filter and sort by tags, filter by where tags _don't_ exist and more. I didn't have to do anything other than model my domain, and Ash took care of the rest for me. Not only that, but it probably did a lot of things for me that I probably wouldn't have thought of, such as supporting multi-tenancy, policies and more.
It really is a lovely tool, I can't say enough good things about it.
Does it have a learning curve? Absolutely! Is it worth overcoming it? Again, absolutely!
Except that it's not like Rails in the sense that in Rails, you will eventually develop extremely difficult to debug race conditions thanks to mutability that Elixir lacks.
Source: Has worked on million-line Ruby on Rails codebase
It doesn't matter as much as you think. I believe this is in part due to how assertive most Elixir code tends to be. [1] These assertions not only aid the LSP and can cause compiler warnings/errors, they also help LLMs just like types do.
Still, every release now contains new type system features. Next up is full type inference. [2] After that will be typed structs.
Can agree with this. I have had some funny hallucinations, though, where it mixes up Elixir keywords with totally unrelated to programming things and then acts very confident that said things are in Elixir. So you just need to be a bit skeptical and double-check it. But that goes with the LLM territory anyway.
Can we say that being a functional language makes it easier for AI to understand and write cleaner code? Basically, there are no mutations of input data and I guess somehow that makes it easier for the LLMs to understand and keep a track of the input and avoid weird and fancy mutations down the call stack.
YMMV, but I think it writes fine unit tests, but really sub par functional or end to end tests that need to check business logic. I think that's just a hard case for LLMS and not an elixir issue though.
I really like Elixir. We’re a small team of a few.
We work with series of timespans a lot in our domain (ag tech irrigation automation), and I needed to write an algorithm that creates the time based “diff” comparison between two or more span series.
I’ve written this code a few times already in Swift (iOS app), Kotlin (Android app), and Python (firmware). Loop based and tricky around the edge cases.
Doing it in Elixir with pattern based recursion was a pure joy. Every single test past the first time I ran it.
I don’t love the Elixir syntax (it’s noise to signal ratio isn’t as good as say, Python); I don’t love the lack of a good IDE experience that really leverages Elixirs model. But I do love the mental computation model of Elixir, and the very simple set of rules, vs some of the other languages I have to work in.
I've been wanting to learn Elixir for a long time but is it worth learning it without knowing Erlang first? I'm not against learning Erlang but just curious if Erlang is a good thing to know before tackling Elixir.
Erlang is definitely worth learning but definitely not required by Elixir.
Learning the concepts that embody Erlang such as tail recursion and function matching, make Erlang worth learning. Erlang is also a special mix of Prolog and Lisp.
To add to this, Erlang is a very simple language that you can learn in just a few days. I don't know Elixir but I assume that, as is the case with Erlang, the more difficult thing to learn is OTP and not the language itself.
For me Erlang was worth learning because it's so interestingly different to many other languages because of its Prolog roots.
I only learned Elixir because the company I currently work for is an Elixir shop. I've basically ignored Erlang since I started here, other than the occasional library being Erlang.
I don't think it's really impeded my ability to learn or use Elixir. But I could also see how learning it and the underpinnings for Elixir could aid understanding too.
It is absolutely 100% _not_ necessary to learn any Erlang at all before learning Elixir. I've been developing with Elixir for 5 years and still have never written a line of Erlang.
You don't need to learn OTP at first either — it'll just slow you down and confuse you. Learn Elixir syntax and semantics, learn how to build a Phoenix app or whatever, then dive into OTP once you're comfortable with the basics.
We've been running Elixir in production for 5+ years and most of our team only know some very basic erlang data structures for working with the :dbg module on live systems.
Erlang knowledge is not needed for building products with Elixir at all unless you want to go very in-depth.
That's pretty cool - what is it if you don't mind talking about it? How do you feel Elixir made it possible or easier. Or is it just something you happened to choose and you could have used Node or Rails or whatever else.
I was a nodejs engineerfor 7 years previously and had a lot of experience it. if you're building a backend, unless you're relying on a specific library or building a microservice, I think elixir/phoenix is a way better stack. being functional and having a pass by value by default, you avoid whole classes of errors you have to learn to look out for in node. While there was some initual challenge setting up autodiscover with libcluster, it means we were able to get away with not setting up a message queue or pubsub system or websocket infrasturcture since all that came out of the box. Additionally, creating services is as easy as adding a controller in rails. just use Genserver and add it to your supervisor file.
TLDR: sure i could have done it in node but it would have been a LOT more work and less reliable
You do not need to know much, if any, Erlang to be productive in Elixir. Some libraries you might call will be written in Erlang, but those tend to have been around long enough that you don't need to look inside. Being able to read the Erlang docs can be helpful, because the OTP has a ton of helpful functions, but that's mostly just learning what Erlang calls its types.
I have never done anything serious with it, because I don't have any use case, it is not a programming language that either our IT, nor customers want running on their servers.
Only thing that always gets overseen in language discussions about which one is best, is that most companies pick languages based on ecosystems and products they buy/adopt, not pick a programming language from a catalog and then go looking for problems to solve with that language.
Unless of course they are a startup trying to get hold of a new domain, many times creating the need for others to adopt a specific programming language, when their product gains enough market share, thus we are back into how (the other) companies pick programming languages.
That is how we end with languages that maybe should never have been mainstream, a lucky product, killer application, market adoption happens, people want to learn the language to get employed, and the adoption circle goes on, thus whatever misconceptions there are matter very little for most programming languages, once they pass the adoption threshold.
There's a real uphill battle for adoption. Can't use it because it's not popular enough and there aren't enough experienced devs. Its not more popular and people don't have that experience because it's not used as much.
Half (if not more) of the things my company is working on right now would just not be a thing if we used Elixir. But instead, we're one of millions of companies re-inventing solutions to the same distributed computing problems using Node & AWS in a less optimal and worse-tested way. Such is life.
Indeed, and hence why for example while I would rather use Smalltalk, Prolog, Lisp or Standard ML, I have to also contend myself with their influences on programming languages and tools that we are actually allowed to use.
I’ve been working with Elixir professionally for the past 7 or 8 years, and I have to say, phoenix and are great, but it’s the repl I miss the most when I’m building in other languages. The ability to interact with a system, ask questions, try code, is crucial when I’m debugging
Could you have at least rewritten some of the obvious AI stuff? "it's not X - it's Y" appears about five times in the first minute of reading, at which point I gave up (after all, I could just ask ChatGPT to generate the article myself)
Some don't use it because the performance on anything other than IO is just bad. This isn't just because its "not compiled", but because it has a scheduler taking up cycles and it enforces immutability, when can be brutal for some tasks when mutability can really speed things up.
I just started learning Elixir recently and I'm honestly loving it. Pattern matching is awesome and how it approaches concurrency and async work was so easy to wrap my head around. Pragmatic Studios has a great tutorial.
I’m skeptical of this claim, where is he getting it from?
“Elixir’s foundations in functional programming…make it easier for large language models to reason about, generate, and test code. LLMs struggle with imperative codebases full of side effects, hidden state, and indirection…”
It seems a larger factor in LLM performance on a given language is the amount of code available to train on.
I've found (specifically using Idris 2, but any functional language with some typing should work) LLM's to write better code in these restrictive languages simply because there are significantly fewer ways to screw up that are possible without causing an error upfront.
In fact, I would even go so far as to say that LLM code assistance may cause a boost in interest in those languages.
If you structure your prompt around small, stateless functions with explicit inputs/output, answers may look cleaner, but that advantage is not at the language level. You can do the same in TypeScript et al and get the same results.
I don’t doubt that anecdotally you’ve had favorable results. However, I’m not aware of any research that backs up this claim. Or forget research - I’m not aware of any simple examples / prompts that would show it in a reproducible way across different LLMs.
> I’m not aware of any research that backs up this claim
These things are literally days old. Claude 4, which is arguably the first truly useful LLM code assistant, released in May. Scientific research proceeds at a glacial pace. I'm just speaking from anecdotal experience. It may be a perceptual illusion, or it may be a real thing. Just my data point.
One could deduce that restrictive languages would naturally result in fewer runtime bugs produced by LLM's since they do the exact same thing for people. For example, Elm is literally designed to produce NO runtime errors, so coding Elm in an LLM (which I haven't done) would ostensibly result in almost all errors being caught upfront.
This is not to say that other types of logic errors, redundancy, etc. wouldn't slip through without human intervention.
Elixir's syntax is very intimidating. We maintain a fork of "bors-ng", I'd very much like to hack around a fix or two, but just stare at the code in awe.
What part of the syntax is intimidating? To my mind, it's not all that dissimilar from e.g. Python, which is not a language about which people express the same feeling.
Structure and control flow feels very Python/Ruby-ish, however, when you get into the depths of pattern matching and binary deconstruction or even macros, Elixir syntax can become somewhat messy. However, the same concepts, once understood, are extremely powerful for parsing or protocol handling.
I have a ton of respect for José Valim and the Elixir core team, I have to say: Elixir just doesn’t mesh well with the kind of infrastructure tooling that’s become standard today. The ecosystem has been growing impressively and there’s a lot to admire, but its philosophy often feels at odds with containerized, Kubernetes-based deployments.
Elixir promotes a "do it all in one place" model—concurrency, distribution, fault tolerance—which can be powerful, but when you try to shoehorn that into a world built around ephemeral containers and orchestration, it starts to crack. The abstractions don’t always translate cleanly.
This opinion comes from experience: we’ve been migrating a fairly complex Elixir codebase to Go. It’s a language our team knows well and scales reliably in modern infra. At the end of the day, don’t get too attached to any language. Choose what aligns with your team’s strengths and your production reality.
If you can't get Elixir to work well in k8s, you're simply doing it wrong. Yeah you can build a lot of what k8s offers on the BEAM on a bare server but you don't have to at all. Elixir offers modern telemetry that works really well with pretty much any monitoring tool, and give you a lot of introspection into the internals of the VM if you need it. "Let it fail" works just fine in k8s, you can run a supervision tree in a container and have it manage process restarts internally just fine, its just an added layer of fault tolerance. Sure, you can't easily have long running stateful processes if you're doing a lot of blue-green deployments, but you probably don't need to do that most of the time.
If you don't know Elixir and the BEAM well, of course you're going to have a bad time. That's true of any language.
phoenix live view is effectively built around the assumption that the server process never dies and never restarts. its a very dubious model for a production deployment.
> what happens when the server restarts / connection is lost / server dies?
> you lose all of the current client state but you can work around this by persisting all the client state somewhere.
> phoenix live view is effectively built around the assumption that the server process never dies and never restarts.
Not exactly, it's built to hold state in memory by default but doesn't assume how you want to handle deploys or server restarts. There's a built in restore mechanism for forms and it's trivial to shuffle state off to either the client/redis/your db[1]. You'd have the same problem if you were storing all your state in memory for any web application regardless of your library choice. Or you conversely have the problem that refreshing the page trashes client state.
So there are two thinks here, you don't have to use live_view to use elixir or phoenix, and if you do you just need to actually think about how you're solving problems. The state can get trashed anywhere for any number of reasons. Tossing on the client and forgetting about it just moves the problem.
> You'd have the same problem if you were storing all your state in memory for any web application regardless of your library choice.
But that's the thing - traditional server-side web applications don't do this. The the stateless request/response cycle of traditional server-rendered apps is a _huge_ advantage from a system design standpoint. State is bad. State is hard to manage correctly over time. Elixir makes it possible to manage this in-memory state relationship better than other languages, but it's still difficult to do at scale regardless.
LiveView turns stateless web applications into stateful web applications, and this is a problem most folks aren't considering when they see developer experience improvements the LiveView project claims. This is _the_ specific tradeoff that LiveView makes, and I wish folks wouldn't handwave it away as if it were trivial to manage. It's not. It's a fundamentally different client/server architecture.
Source/disclaimer: I work at a large company with a large LiveView deployment, we have spent a ton of time and money on it, and it's a pain in the ass. I still love Elixir, I just think LiveView is oversold.
I guess my quibble is that I’ve talked to Jose and Chris about this and I don’t think they’re overselling it. The caveats are in the docs and they expect you to understand the tools.
And realistically there are cases where I’d use another tool.
the way live-view is sold is some kind of alternative to writing javascript. if you have a very rich client side application then you can easily end up with a bunch of state which would be in the clients memory but now is in the servers memory. but if its in the servers memory the data ends up being much more fragile because any failure of the client or the server means the live view state is lost. whereas if the data was just in client memory then it would only be lost if there is a problem in the browser. ideally people would write applications that are tolerant to both faults. but i think in practice live-view practitioners just ignore the problem and then you are left in a worse situation.
i realize there is still a dataloss problem when there is state on the client but there is a lot of simple stuff that causes problems if you are effectively reloading the page if the server disappears due to a redeploy or a crash.
for example i'm reading an email in my message client. i've scrolled half-way down the email. but now the server crashes i reconnect to live view and my scroll position when reading the email is reset.
when i look at live view i feel like its written by people that have never deployed something in production. of course this is not really true but i feel like it would be better if live-view people were more honest about the tradeoffs. its a very complicated situation and having some bad outcomes might be worth the increase in developer productivity but i feel like live-view people just ignore the bad outcomes.
also, take a cloud deployment. websockets seem to be an inherent problem in cloud deployments especially AWS. as far as i know AWS does not expose some event to a instance that is part of a load balancer that it is about to die. ideally if you have a websocket instance with a client and you realize you are scheduled to be reaped you would message the client that it needs to reconnect. then the client would reconnect to a server that would not be reaped and everything would be dandy. but AWS doesn't seem to have this functionality (or its not easy to implement!) but more importantly live view does not expose any kind of hooks so you can have 'safe' server redeployment out of the box.
I'm not sure who from the core group of developers is overselling it in the way you're claiming. Yeah, I wouldn't try to build figma or gmail with liveview, but I'd be fine building an app for a bank for example. Tools exist in a mesh of other tools and problem spaces where they may or may not be appropriate.
it really depends on what you are doing. if you have a complex application then the automatic recovery might not be enough for a fault free user experience. i feel like live view is sold as some kind of magic where the developer does not have to write javascript and you can just implement the server side purely in elixir as you would javascript without writing to a database, or some session storage. but if you do this then you are in a worse situation than javascript when it comes to network faults, or server processes restarting.
Sure, if your a company which is fully bought into ephemeral containers running on Kubernetes then Elixir is probably not going to be a great fit for you. I have once introduced it into a company like that and eventually the same thing happened, the application got rewritten in a language that fits the paradigm better.
If I were starting a new company today though I'd probably go with Elixir, and then I simply wouldn't bother with containers, Kubernetes, and schedulers. Just run some servers and run the application on them, let them cluster, and generally lean into the advantages.
most people/companies who think they need kubernetes don't actually need it. you are not google or amazon. and with erlang/elixir that's likely even more true.
> if your a company which is fully bought into ephemeral containers running on Kubernetes then Elixir is probably not going to be a great fit for you
As a community, we have got to stop saying this stuff. It's false. Nothing about Elixir or k8s precludes using the other. Elixir applications can and do run just fine in containers and k8s deployments. In fact, they're complementary: https://dashbit.co/blog/kubernetes-and-the-erlang-vm-orchest...
Elixir has a Ruby on Rails approach which is kind of all in one. Not everyone’s cup of hot chocolate.
Erlang is low level, lightweight processes and message passing - perfect for micro-services and containerisation.
What Erlang lacks are high level web-oriented packages, i.e. markdown conversion, CSS and JavaScript packaging, REST (not quite true: cowboy is fantastic) - for which though Erlang was never intended.
However the cool thing is that you can combine both in the same project, allowing you to have high level Elixir and low-level process management in one project. This is possible because both use the same virtual machine - BEAM.
Erlang isn't really that much lower level than Elixir. The Elixir syntax is just a bit different and they've improved a few things like string handling. Processes are still processes.
We look at K8s more like "the Cloud Operating System". Many of its capabilities are more valuable for other runtimes, but that doesn't mean that Elixir is a bad fit with it.
For example, the Erlang VM clustering can make use of K8s for Service Discovery. You can do ephemeral containers and use readiness probes to create a " hand over" period where new instances can sync their data from old, about-to-be-replaced instances.
Did you do hot updates? I ser that is mention in the post, but I thought the community has walked away from it? Or at least that its mixed feelings about it?
No, you're not alone. After learning Lisp, structural editing and REPL-driven-development, I just don't feel like needing to learn new languages no matter how powerful they seem to be. Lisps like Clojure are highly pragmatic and offer something fundamentally different from the endless parade of syntax-heavy languages that dominate the mainstream.
Once you've experienced the fluidity of paredit or parinfer, where you're editing the structure of your code rather than wrestling with textual representations, going back to manually balancing brackets, fixing indetnation and carefully placing semicolons feels like reverting to a typewriter after using a word processor. The code becomes malleable in a way that's hard to appreciate until you've lived with it.
And the REPL changes everything about how you think and work. Instead of the write-compile-run-debug cycle, you're having a conversation with your running program. You can poke at functions, test hypotheses, build up solutions incrementally, and see immediate feedback. It's exploratory programming in the truest sense - you're not just writing code, you're discovering it.
The homoiconicity - code as data - means you're working in a language that can easily reason about and transform itself. Macros aren't just text substitution; they're proper AST transformations. This gives you a kind of expressive power that most languages can't match without tremendous complexity.
So when the latest trendy language appears with its new syntax and novel features, it often feels like rearranging deck furniture. Sure, it might have nice type inference or clever concurrency primitives, but you're still stuck in the old paradigm of fighting syntax and losing the conversational flow of development.
You've tasted something closer to the pure essence of computation, and it's hard to go back.
I used Clojure and it has same goals as bigger-grammar languages, like overloaded function definitions, casting/type-hinting, method calls etc, it just achieves them in a clunkier way.
while i love s-expressions, i am not aware of any language outside the lisp ecosystem that supports it natively. are you saying that you are put off that elixir is not lisp?
i am interested in clojure, but i am put off by it using the java run time. ;-)
> i am interested in clojure, but i am put off by it using the java run time
Clojure runs not only on Java - you have Clojurescript, you have babashka and nbb, you have Clojure-Dart — if interested in building Flutter apps, you can even use Clojure with Python libs. If you need to target Lua, there's Fennel, which is similar as it's inspired by Clojure.
For me - Clojure is a hands-down best medium for data manipulation - there's just nothing better out there to explore some data - investigate APIs; sort, group, dice and slice any kind of data - CSVs, JSON, etc. Nothing else simply can match the joy how one could incrementally build up complex data transformations, it makes it incredibly productive for the "let me just quickly check this shit" scenarios that can easily turn into full analyses. REPL-driven nature of it makes it so much fun - you feel like you're playing a videogame.
I honestly wish every programmer knew at least some Clojure. I lost count of how many times I gave up on figuring out complex jq syntax and reached for Clojure instead. Or the times I'd quickly build a simple Playwright script for reproducible web-app bug trapping or quick data scraping that saved me hours of frustration and manual clicking.
Am I missing something or is there isn’t even an official LSP available for Elixir? For me, that looks like a red flag. From what I see, DX in VSCode is barebones.
> Elixir abstracts that away and leaves a ruby-like language that hides much away - which good and fine.
Processes, message passing, and behaviours are all completely first class in Elixir. There's no hiding. `spawn` is `spawn`. `send` is `!`. `GenServer` is `gen_server`. `@behaviour` is `-behaviour(...)`. The entire Erlang stdlib is available directly.
We use processes, messages, and behaviours all the time in regular Elixir work.
Elixir adds a different syntax (note that I did not say better), a macro system, a protocol system, its own stdlib functionality, some better defaults, and a build tool.
It's perfectly fine and reasonable to prefer Erlang (I learned Erlang before I learned Elixir), but for the benefit of other readers, they are really not that different. The distance between Elixir and Erlang is very small. They could almost be seen as dialects.
I have come to the simple conclusion that yeah if a tech is great and people are not launching products internally or as startups then maybe it's time to introspect.
if using elixir supposedly gives a competitive advantage, why aren't companies using to launch new products - both existing and startups.
a lot of those things quoted in the article are present on the jvm platform or through containers.
and btw some of those companies listed have migrated away from elixir e.g brex and discord.
I’m not so sure that popularity has any kind of correlation with capability, quality, viability, etc. That has more to do with marketing, social media trends, buzzword compliance, and what’s caught the eye of the current crop of resume-driven developers and managers.
Tools like Elixir which are focused on solving problems, aren’t flashy or easy for web dev influencers (yes, they’re a thing) to tout, and have a bit of higher barrier to entry are probably at a disadvantage in this way, even if they’re actually quite good.
This is why the industry is stuck on a revolving door of JS frameworks and the n-hundreth React self-reinvention. It’s not about how good any of this actually is, it’s about how well it scratches the itch for that new car smell while also being easy to pick up and make grand declarations on social media about.
Companies _are_ launching products with it ; that you aren't hearing about it is more about communication & leverage, than about their existence.
A while back there was an effort to give more publicity on precise cases here https://elixir-lang.org/cases.html ; I think the effort is now moving to advertising the platform outside Elixir circles (e.g. more generalist conferences).
FWIW, I'm working on https://transport.data.gouv.fr, Elixir-based since 2016, the National Access Point to transportation data, which includes a business specific reverse proxy with a 3x YoY growth, with no plans to migrate :-)
3 out of 5 of all the phone calls you've ever made was managed by a box somewhere running the Erlang VM (BEAM) which Elixir gets all its concurrency and parallelism from.
And no, Discord has not moved away from Elixir. While they have adopted Rust for certain parts of their infrastructure, Elixir remains a core part of their backend, particularly for real-time communication and chat infrastructure.
to learn what? that the language was not good enough? that it wasn't marketed well enough? that there was not enough community support? not enough word of mouth?
lisp users say they have a competitive advantage, as do smalltalk users. even pike at a time had a competitive advantage in that it was/is more performant than other similar languages.
some of us in the pike community kept asking ourselves why pike is not more popular. the syntax is not obscure. roxen was a killer webdev server, 10 years ahead of its time. but no takers. why? (probably a mix of lack of marketing and community support/encouragement from the financial backers, but other languages become popular without backing, so what gives?)
my point is that most times there is nothing you can do. unless you have the marketing power of sun (java) or google (go, etc), popularity of a language is mostly a case of luck and serendipity (ruby, python) or filling a unique need that no other language could (javascript, rust)
Elixir also does not stand alone - the storied history of Erlang/BEAM in mission-critical distributed systems needs no introduction. Elixir lives within, and benefits from, that same ecosystem of libraries and tools.
So yeah I'm not sure what you believe there is to "introspect" about, nor to what end.
> For those I managed to confuse, “glass-to-tin” just means “front-to-back” or “from the screen to the back end”.
So like a thin mirror? Which only serves to show the viewer back to themselves? And which also consists of just two extremely simple parts, that is, two panes/sheets of uniform materials, and nothing more?
How do you even come up with this metaphor for a web-based application? It's horrible!
Sorry, it didn't land for you. It's something I've used for a while ("glass" for the screen, and "tin" for the back-end). Perhaps I'm showing my age or my Aussie slang. Thanks for reading, in any case!
You use the phrase twice in the article. Could I ask you to put an asterisk by the first one too?
(I came across it, stopped reading the article to Google it, couldn't find it so came to HN to search the comments and then went back to the article and saw the asterisk later on)
I’m genuinely surprised how much controversy this statement has caused. It’s something I’ve said many times in a professional environment and literally no one has ever picked me up on it. Makes me wonder if they were _ever_ listening …
I agree with most commenters that Gleam seems like the thing that’s going to solve a lot of the big problems I have with Elixir.
I didn’t read a lot about Nx and EXLA in the comments, so I thought I’d share my view:
In my opinion, that’s not a strong argument for Elixir, because pretty much every language has libraries like this. Rust, famously, never stops inventing these libraries (https://arewelearningyet.com/), and to illustrate my point, here are some libraries for niche(-ish) languages:
They might be suitable for researchers or projects building networks from scratch, but this is already difficult with a library that plays along. For most people, it’s about fine-tuning, combining, and doing inference on existing models (and weights).
People like to criticize PyTorch, but in fairness, with it I can do useful things with recent models (which matters at the speed of things) pretty much the day they have their open source release (thanks to the transformers library). There exists an equivalent to transformers for Elixir (https://github.com/elixir-nx/bumblebee), but it doesn’t support the top 10 trending models on HuggingFace, which is a problem if you want to use them. Qwen 3, for instance, arguably the most useful open source model family at the moment, isn’t supported at all. And this is the issue all of these libraries face: they are not useful for the majority of people needing libraries like this out there.
Also, PyTorch is really well optimized, and there is a good reason that vLLM (yes, it’s not the fastest but pretty fast, supports almost everything, and is the de facto standard for open source LLM inference) is written in Python and PyTorch. Things like Flash Attention 2 are crucial for LLM inference and still hard to find. Yes, OpenXLA is technically very sophisticated, but I never got it working every time I wanted to use it, and JAX seems more comfortable if you want to use TPUs.
It’s still a very strange development that Python runs the AI revolution. Multi-node training might be a lot of fun with Elixir, but here performance (especially making sure the CPU is not stalling the GPU) is vital, which might make BEAM not an ideal choice.
There is hope though. Recently there have been some interesting developments in the Rust world (https://luminalai.com), and of course no HN comment about training and inference is complete without mentioning TinyGrad. But Elixir simply doesn’t make sense to me (for neural networks). I’m sorry.
I've been writing Elixir on-and-off since 2017 for personal projects and since 2024 professionally, at a big tech company.
The two experiences couldn't be more different. While I loved the great development speed for my personal projects, where I am writing more code than reading it, joining an existing project needs the opposite, reading more code than writing it. And I can only repeat what many people say, dynamic typing makes this so much more difficult. For most code changes, I am not 100% certain which code paths are affected without digging a lot through the code base. I've introduced bugs which would have been caught with static typing.
So in my conclusion, I'm bullish on gleam, but also on other (static) languages embracing the cooperative green-thread/actor model of concurrency like Kotlin (with JVM's virtual threads). (On another note, I personally also dislike Phoenix LiveView and the general tendency of focusing on ambiguous concepts like Phoenix Context's and other Domain Driven Design stuff)
I worked a year or so at an Elixir shop, and this mirrors my experience. I had to navigate to call sites to understand what I was being passed and type hints were not sufficient. Dynamic typing fails larger orgs/teams/codebases.
Fun to develop and solo administer. Small teams with a well known codebase can do amazing things. I work at orgs with multiple teams and new hires who don't know the codebase yet.
For me, the sweet spot is Go.
Out of curiosity, at the tech company, did the team use typespecs and dialyzer?
The lack of type hint for function parameters is definitely a productivity killer (in my case).
There are type hints for function parameters. With some care and guards, Dialyzer can be somewhat helpful.
What actually drove me nuts was absence of guards and meaningful static analysis on return values. Even in my small but nontrivial personal codebase I had to debug mysterious data mismatches after every refactor. I ended up with a monad-like value checking before abandoning Elixir for my compiler.
Fully agree with this based on similar experiences. IME most devs hired without previous Elixir/Phoenix experience don’t end up liking the tech stack very much, even though they become productive quite quickly and don’t struggle too much with Elixir. A lot of Elixir/Phoenix fans make the mistake of thinking that everyone is going to love it as much as they do once they get up to speed.
Isn't there some kind of optional typing in Elixir?
What you're describing are the same uncertainties I've used to have writing PHP a long time ago, but since using optional types and PHPStan checker, it kind of serves as a compiler pass that raises those issues. The benefit being that I still can be lazy and not type out a program when I prototype the problem on my first pass.
>Isn't there some kind of optional typing in Elixir?
It’s in the works and recent versions of the compiler already catch some type errors at compile time, but it’s nothing remotely close to what you get from Typescript, or from any statically typed language like Go, Rust, Java, etc.
> Isn't there some kind of optional typing in Elixir?
Sort-of. Developers provide typespec which is like a hint and use dialyzer to find issues before runtime.
This is why Gleam exists.
Also, Gleam fully supports Elixir packages.
I am now super curious which big tech company is betting on Elixir?
Nubank, Latin America's most valuable bank, relies heavily on Elixir and even acquired Plataformatec, the company where Elixir was created.
A blog post by them about this: https://building.nubank.com/tech-perspectives-behind-nubanks...
Wasn't Nubank the Clojure posterchild not long ago?
Are they moving from Clojure to Elixir, or adding it?
The referenced post is from 2020, and nubank still posts clojure content and sponsors the big clojure conference, so I’d be shocked if they were dropping clojure.
Their tech stack is probably enormous, it wouldn’t surprise me if they’re using both for different things
Also the referenced post is about them acquiring plataformatec, not about using elixir. Jose Valim (the creator of elixir) left plataformatec after the nubank acquisition in order to continue developing elixir, I've never heard of nubank using elixir, afaik they're solidly a clojure shop with no plans on changing.
it's just an internal I/O-bound project, where BEAM concurrency makes lots of sense. Grown from an engineer's side project as it was useful and working well, not a company-wide effort to bet on Elixir
Am I the only one who never tried Elixir just because it has no strict typing? Seems very hard for me to go back to a language with dynamic typing. Maybe I'm just wrong and I should give it a try.
It is alleviated quite a bit bz its pattern matching capabilities combined with the "let it crash" ethos.
They have a success typing system (which isn't very good) and are working on a fuller system (which isn't very mature).
If typing is the only thing keeping you out, have a look at Gleam.
Having worked with Elixir professionally for the last six years now, it is a very mature platform, very performant and offers many things that are hard in other languages right out of the box.
> combined with the "let it crash" ethos
I see this phrase around a lot and I wish I could understand it better, having not worked with Erlang and only a teeny tiny bit with Elixir.
If I ship a feature that has a type error on some code path and it errors in production, I've now shipped a bug to my customer who was relying on that code path.
How is "let it crash" helpful to my customer who now needs to wait for the issue to be noticed, resolved, a fix deployed, etc.?
>How is "let it crash" helpful to my customer who now needs to wait for the issue to be noticed, resolved, a fix deployed, etc.?
Let it crash is more about autorestarting and less about type bugs. If you have a predictable bug in your codepath that always breaks something, it just means you never tested it and restarting will not fix it. But this kind of straightforward easy to reproduce bugs are also easy to test the hell out of.
But if you have a weird bug in a finite state machine that gets itself into a corner, but can be restarted -- "let it crash" helps you out.
Consider hot reload -- a field exists in a new version of a record, but doesn't exist in a old one. You can write a migration in gen server to take care of it, but if you didn't and it errored out, it's not the end of the world, it will restart and the problem will go away.
I wonder what production monitoring is like for that. Does Elixir have a good monitoring platform like NewRelic for tracking the state of these processes?
Elixir has OpenTelemetry bindings which integrate into most of these platforms. At work, we use DataDog.
The core of a properly built, resilient/robust system is that you have compartmentalized code into different small erlang processes. They work together to solve a problem. A bug in one is isolated to that particular process and can't take the whole system down. Rather, the rest of the system detects the problem, then restarts the faulty process.
The reason this is a sound strategy is that in larger systems, there will be bugs. And some of those bugs will have to do with concurrency. This means a retry is very likely to solve the bug if it only occurs relatively rarely. In a sense, it's the observation that it is easier to detect a concurrency bug than it is to fix it. Any larger system is safe because there's this onion-layered protection approach in place so a single error won't always become fatal to your system.
It's not really about types. It's about concurrency and also distribution. Type systems help eradicate bugs, but it's a different class of bugs those systems tend to be great at mitigating.
However, if you do ship a bug to a customer, it's often the case you don't have to fix said bug right away, because it doesn't let the rest of the application crash, so no other customer is affected by this. And you can wait until the weekend is over in many cases. Then triage the worst bugs top-down when you have time to do so.
In addition to the other fine replies, it helps to remember that Erlang/BEAM, and by extension Elixir, comes from the telephony world. If something crashes in that world, you'd far rather terminate a phone call spuriously than bring the whole system down. (And in the 1990s, when the main alternative was C, and not just C as it may be today but 1990s C specifically, that was a reasonable concern.) Erlang is optimized for a world where that's a reasonable response to a failure. I've also used it in a context where a system makes a persistent connection up to a controller, and if either side crashes they automatically reconnect. "Let it crash" is a reasonable response to a lot of issues that can arise.
The farther you get from that being an issue, the less useful the "let it crash" philosophy becomes, e.g., if I hit "bold" in my word processor and it fails for some reason, "let it crash" is probably not going to be all that helpful overall.
I have seen systems that "should" have been failures in the field be held together by Erlang's restart methodology. We still had to fix the bugs, but it bought us time to do it and prevented the bad deployments from being immediate problems. But it doesn't apply to everything equally by any means.
Okay but “static typing avoids the crash to begin with”, is what everybody from the static typing world is thinking reading all these very long responses that don’t address this very basic idea.
I like to measure languages by "what do I miss when I leave them".
I used Erlang professionally for about 5-6 years.
I have not missed "let it crash".
It's an interesting idea that should be grappled with, but Erlang users have this tendency to very badly strawman their opposition and spout their propaganda like it's still 2005 and the rest of the world has just been twiddling their thumbs, gormlessly ramming into brick walls as they scale up and are just flabbergasted about how to handle the problems of scale, when in fact, to a first approximation all of the large systems in the world that are reliable are also not written in BEAM. There are other solutions to the problem. Strong types are a big component of how I deal with this in my current code, yes. It's not 100% a solution, but then, I can have both anyhow so I generally do.
I was just providing context. When trying to understand BEAM it is always helpful to have in the back of your head that it was written for telephony, with all that implies.
Apologies, I should’ve directed my reply to somebody else - your take was well balanced.
A discussion by Joe is helpful here; It contains some code: https://erlang.org/pipermail/erlang-questions/2003-March/007...
"Crashing is loud" below is a phrase to combine with "remote error recovery" from the link above. Erlang/OTP wants application structure that is peculiar to it, and makes that structure feel ergonomic.
> If I ship a feature that has a type error on some code path ... How is "let it crash" helpful to my customer?
The crash can be confined to the feature instead of taking down the entire app or corrupting its state. With a well-designed supervision structure, you can also provide feedback that makes the error report easier to solve.
However, while a type error in some feature path is a place that makes type annotations make sense, type annotations can only capture a limited set of invariants. Stronger type systems encode more complex invariants, but have a cost. "Let it crash" means bringing a supervisor with simple behavior (usually restart) or human into the loop when you leave the happy path.
> "Let it crash" means bringing a supervisor with simple behavior (usually restart) or human into the loop when you leave the happy path.
If a "human" has to enter the loop when a crash occurs, this limits the kind of system you can write.
I had to work on a system where a gen server was responding to requests from a machine, sent frequently (not high frequency, but a few times per second.) If for some reason the client misbehaves, or behaves properly but happens to use a code path that has a type error, the only option given by "let it crash" was to, well... crash the actor, restart the actor, then receive the same message again, crash the actor, restart the actor, etc... and eventually you crash the supervisor, which restarts and receives the same message, etc...
Let it crash definitely wasn't meant to be a cover for poorly typed code.
It's much more suitable as a replacement for adding try / catch everywhere and having to manually bubble exceptions.
Crashing is loud. You will get crashes in your logs. And you can let it happen because those crashes won't disrupt anything else - that's what the message passing gets you.
So sure, the code with the error won't work (it wouldn't work in any language - you can make an error in all of them), but you will get a nice, full stack trace and the other processes in your VM won't be impacted at all. You won't bring down the service with a crash. Sometimes this is undesirable - you could deploy a service where the only endpoint that functions is the health check - but generally people don't do that.
> And you can let it happen because those crashes won't disrupt anything else
Isn't that also covered at the framework (rails, django, whatever) level in other languages ?
I feel like the other comments I see here, are not expressing the deeper point, and you're asking to really understand something, so that's what you care about? So I'm sorry to pile on when you've got like a dozen good answers, but.
Let It Crash refers to a sort of middle ground between returning an error code and throwing an exception. It does not directly address your customer's need, and you are right that they are facing a bug.
So if you were to use Golang with Let It Crash ethos, say, you would write a lot of functions with the same template: they take an ID and a channel, they defer a call to recover from panics, and on panic or success they send a {pid int, success bool, error interface {}} to the channel -- and these are always ever run as goroutines.
Because this is how you write everything, you have some goroutines that supervise other goroutines. For example, auto-restart this other goroutine, with exponential backoff. But also the default is to panic every error rather than endless "if err != nil return nil, err" statements. You trust that you are always in the middle of such a supervisor tree and someone has already thought about what to do to handle uncaught errors. Because supervision trees is just the style of program that you write. Say you lose your connection to the database, it goes down for maintenance or something. Well the connection pool for the database was a separate go routine thread in your application, that thread is now in CrashLoopBackoff. But your application doesn't crash. Say it powers an HTTP server, while the database is down, it responds to any requests that do not use the database just fine, and returns HTTP 500 on all the requests that do use the database. Why? Because your HTTP library, allocates a new goroutine for every request it handles, and when those panic it by default doesn't retry and closes the connection with HTTP 500. Similarly for your broken codepath, it 500s the particular requests that x.(X) something that can't be asserted as an X, we log the error, but all other requests are peachy keen, we didn't panic the whole server.
Now that is different from the first thing that your parent commenter said to you, which is that the default idiom is to do something like this:
With a bit of discipline, this emulates Haskell algebraic data types which can give you a sort of runtime guarantee that bad code looks bad (imagine switching on an enum `case TypeFoo`: foo := arg.(Foo)`, if you put something wrong in there it is very easy to spot during code review because it's a very formulaic format)So the idea is that your type assertions don't crash the program, and they are usually correct because you send everything like a sum type.
Thank you for this very detailed explanation! I think between this and the other very welcome replies, I think I have discovered what I didn't understand: that "let it crash" addresses a different set of problems than static types, but that a dynamic type system can still be helpful in avoiding type errors in the first place, if it leads you to design data structures in a certain way.
Thanks for your answer! I already checked Gleam several times and it looks amazing. The ecosystem just doesn't feel mature enough for me yet. But I can't wait for it to grow.
True. There is inter-op with both Elixir and Erlang, but thsts like early TypeScript.
If you're at all interested, I'd suggest doing the basic and OTP tutorials on the Elixir Website. Takes about two hours. Seeing what's included and how it works is probably the strongest sails pitch.
Well written typespecs + dialyzer catches most things you’d want to catch with a type system: https://hexdocs.pm/elixir/typespecs.html
There is also pattern matching and guard clauses so you can write something like:
def add(a, b) when is_integer(a) and is_integer(b), do: a + b
def add(_, _), do: :error
It’s up to personal preference and the exact context if you want a fall through case like this. Could also have it raise an error if that is preferred. Not including the fallback case will cause an error if the conditions aren’t met for values passed to the function.
Writing typespecs (+ guards) feels really outdated and a drag, especially in a language that wants you to write a lot of functions.
It reminds of the not-missed phpspec, in a worst way because at least with PHP the IDE was mostly writing it itself and you didn't need to add the function name to them (easily missed when copy/pasting).
I wouldn't lump guards and typespecs together. Guards are a runtime feature of erlang/elixir's excellent pattern matching.
Typespec is an opt-in type hint for develop and build time.
True but by using guards + pattern matching structs you can approximate type hinting, but it feels cumbersome and more of a workaround than a real solution.
I'm of the opinion that Erlang/Elixir are terrible for repeat tasks like a standard CRUD server over a SQL database. Because yes, it IS cumbersome! Behaviors and type hints only get so far, and it is exhaustingly slow to sit with epgsql in the REPL to figure out what a query actually returns.
I find them much better suited for specific tasks where there is little overlap or repetition.
I’d recommend it. I used to think I needed statically typed languages to write sound code, but after enough time with Elixir (10 years professionally and going) I really don’t believe that to be true… A huge portion of my change of heart is due to Elixir (and Erlang) being functional and only having a handful of types:
atom, binary, boolean, function, list, map, pid, reference, integer, float, and tuple
There are a few others but they are generally special cases of the ones above. Having so few data types tends to make it much more obvious what you’re working with and what operations are available. Additionally, because behavior is completely separate from data it’s infinitely easier to know what you can and can’t do with a given value.
Ruby being dynamic drove me insane at times, but Elixir/Erlang being dynamic has been a boon to productivity and quality of life. I recently had to write some TypeScript and was losing my mind fighting the compiler, even though I knew at runtime everything would be fine. Eventually I slathered enough “any” on to make the burning stop… But! That’s something I haven’t had to do in years, and it was 100% due to type system chicanery and not preventing a bug or making the underlying code more sound.
There are still some occasions where having some static typing would be nice— but they’re pretty rare and often only for things that are extremely critical or expensive to fix. And IMHO even in those cases, Elixir’s clarity and lack of (implicit) state generally make up for it.
Here's my take as TS dev. You just never learned to use types in the first place where there is very little ambiguity on any types anywhere because there is close to no any's used. Sounds like you guys get high and mighty on your tunnel-visioned copium—I mean I used to write JS for god's sake and thought it was okay. And I remember when I first tried TS felt annoyingly hampered by having to actually use interfaces properly.
Sure, the nature of Elixir probably makes it easier but I find little joy in dynamic whack-a-mole and mental gymnastics to infer types instead of fricking actually being able to see them immediately.
I could go commando in TS as well and switch to JS and JSDoc, leaving everything gradually typed and probably be fine but I'd feel terribly sorry for anyone else reading that code afterwards. It'd be especially silly since I can now just infer my auto-generated Postgres zod schemas with little effort. Moreover, a good type system basically eliminates typing-related bugs which you guys apparently still have.
So please, don't over-generalize just because you think you got it figured out.
Lmao. This has to be the funniest comment I’ve ever read on here. I can assure you, the only copium being huffed is by you, mate. I have written Scala, Swift, Java, and more (including TypeScript). I have zero trouble with type systems, but I have wasted enough time fighting them for little real world benefit. In Elixir, and this is the best part, I don’t fight type bugs. You probably do because type erasure means you can still have them if someone has mistyped something or shit on something at runtime— the joys of JavaScript.
It sounds like you’re really trying to justify something and that’s great for you. I’m really happy for you. Keep it up. May you soar where no junior dev has dared to soar before. God speed.
Hah. Sure buddy, Mr. Sr Dev. Sorry if I offended you and your vast experience. Without types there definitely aren't type bugs, I grant you that, and JVM languages are quite different to TS. I don't know if your argument on type erasure is any better than advocating for dynamic typing but it definitely happens when you just start throwing anys.
And look, I'm first to admit that TS type system isn't perfect (and it can cause some devs to go overboard) but I have read my share of Python scripts that were read-only from the minute they were born.
And please, your condescension just sounds insecurity to me. It's highly amusing though that you try to play me down as a silly junior dev, I'm quite satisfied that my original assessment was correct.> I'd feel terribly sorry for anyone else reading that code afterwards.
I feel terribly sorry for people that have to read typescript and work with TS zealots
It's not so bad in Elixir for various reasons. Firstly, they're doing some work on set-theoretic types.
https://hexdocs.pm/elixir/main/gradual-set-theoretic-types.h...
There's also tooling like dialyzer, and a good LSP catches a lot too. The language itself has some characteristics that catch errors too, like pattern matching and guard clauses.
With all that said, I'm still very keen for static typing. In the data world we mostly start with Python without mypy, and it's pretty hard to go back.
I went from a Go shop to an Elixir shop and a year or two later went back to a Go shop.
The eng department velocity will slow as code complexity grows and teams change. Dynamic typing makes this worse.
I believe you meant static typing. There's active ongoing work in this space, and Elixir is actually gradually typed now. You can read more about it in the docs: https://hexdocs.pm/elixir/gradual-set-theoretic-types.html
I used it being a big proponent of the TS type system and I definitely missed it greatly.
They are actively shipping a type system for Elixir though, which as far as I understand is pretty similar to TS so, great!
Type systems in this space seem to take a long time and never quite reach completeness. At least that's the experience I've taken away from occasionally glancing at Erlang's Dialyzer project every now and again which I don't think has ever reached any semblance of the maturity of something like TypeScript.
But pattern matching in Erlang does do a lot of the heavy lifting in terms of keeping the variable space limited per unit of code which tends to reduce nesting and amount of code to ingest to understand the behavior you care about at any moment.
Generally I find static typing to be overrated, even more so with elixir due to pattern matching and immutability. I think elixir’s set-theoretic types will be a nice addition and will provide some compile-time safety checks without needing to explicitly define types for everything. It remains to be seen how far they’ll take this approach.
Biggest benefit of typing in TS is just autocomplete that knows to filter down suggestions to field name of the object type before the dot. That and constants without typos. That, exhaustive maps and interface implementations are really good to not forget things that have to be done outside of the currently open file.
really you wind up making only a handful of type errors that make it into prod.
there are other things that contribute to this like pretty universal conventions on function names matching expected outputs and argument ordering.
it does suck hard when library authors fail to observe those conventions, or when llms try to pipe values into erlang functions, and yes, it WOULD be nice for the compiler to catch these but you'll usually catch those pretty quickly. you're writing tests (not for the specific reason of catching type errors), right? right?
I let the LLM write my tests. And when they fail it just rewrites the tests to pass.
I tried it for a job interview, and it was awful - because of no static typing. I spent most of my time tracking down dumb type errors, compounded by various language footguns (I can't remember exactly, but I think for example making a typo on a field name in a for loop condition is treated as "condition false" and so the for loop just doesn't do anything, no error).
It seems like the Elixir/Erlang community is aware of this, as is Ruby, but it's a rather large hole they have to dig themselves out of and I didn't feel particularly safe using the tools today.
I've heard a lot of good things about the Erlang runtime and I did really like Elixir's pipe operator, so it was unfortunate.
Pattern matching makes up for the lack of static typing to me. It provides nearly all the same benefits especially when used with guard clauses.
You can also peek inside objects and check for types and values of nested properties. In other languages you’d need to create composite types or even duplicate or extend types. In Elixir, all that is for free. I see that as much more powerful than types.
Elixir is a strongly typed language (as opposed to a weakly typed language like JavaScript or Perl). You cannot, for example, do `"4" - 1` in Elixir. Dynamic vs static typing is a mostly orthogonal scale, where Elixir is (mostly) dynamically typed.
There are some very sharp Computer Scientists who believe static typing is unnecessary. Joe Armstrong (co-designer of Erlang) once said: "a type system wouldn't save your system if it were to get hit by lightning, but fault tolerance would"
I've never had a system crash from a lightning strike, fault-tolerant or otherwise. I have had systems crash from null pointer errors though, and fault-tolerance did nothing to fix that except turn a crash into a crashloop.
I have the same attitude toward overly permissive type systems that I do toward the lack of memory safety in C: People sometimes say, "if you do it right then it isn't a problem," but since it objectively IS a problem in practice, I would rather use the tool that eliminates that problem entirely than deal with the clean-up when someone inevitably "does it wrong."
We had a cluster of servers, dynamically scaling up and down in response to load, and one day started seeing errors where an enum string field had an impossible value. Imagine the field is supposed to be "FOO" or "BAR" but one day in the logs you start seeing "FOO", "BAR", "GOO", and "CAR". Impossible. "GOO" and "CAR" did not exist in the code, nothing manipulated these strings, yet there they were.
Long story short, a particular machine that joined the cluster that morning had some kind of CPU or memory flaw that flipped a bit sometimes. Our Elixir server was fine because we were matching on valid values. Imagine a typed language compiler that makes assumptions about things that "can't" happen because the code says it can't... yet it does.
Depends how you use the statically typed system.
For example
This will skip bad messages and be statically typed in the valid case.I am not sure I want the system to continue operating in that scenario. You have corrupted hardware that could be trashing other records. What if it is flipping bits on financial transactions?
While I greatly appreciate elixir it is completely malplaced to contrast fault tolerance and type systems - they solve very different needs.
As such fault tolerance does not guarantee that you MRI scanner does not kill your patients.
You likely want both.
It's likely Armstrong conflated the two there because a significant part of the fault tolerance of Erlang comes from the loose coupling via message passing between components, which in no small part is tied to the dynamic typing. It's a Postel's law thing, being generous in what you accept and strict about you send.
Elixir's seamless pattern matching paradigm, IMO, largely negates the need for strict typing. If you write your function signatures to only accept data of the type / shape you need (which you are incentivized to do because it lets you unpack your data for easy processing), then you can write code just for the pretty path, where things are as expected, and do some generic coverage of the invalid state, where things aren't, rather than the norm in software development of "I covered all the individual failure states I could think of". This generic failure mode handling, too, greatly benefits from dynamic typing, since in my failure state, I by definition don't know exactly what the structure of my inputs are.
Yep, I have written and maintained several large scale applications In elixir and live the computation model.
However,elixir depreately needs proper types. IMHO the needs for types are in no means negated by pattern matching, and I also see hints at why you would say so.
> If you write your function signatures...
The point of types is worry less refactoring.
If you work at a place where you can define the arhicture for the entire lifecycle of the application without ever needing to Refactor, then sign me up! I want to work there.
no, but effort is a finite resource so it justifies why they didn't bother.
Well, the people behind elixir seems to have accepted that typing is necessary.
I see this story on an on: some hacker makes a language, they hate types because they want to express themselves. The languages gets traction. Now enterprise application and applications with several devs use it and typing gets essential - types will then gradually be added.
sure, a few years behind typescript/mypy isnt really so bad for a language without a microsoft or a google behind it, is all im saying.
> isnt really so bad for a language without a microsoft or a google behind it, is all im saying
What? Elm was literally the result of a single grad students side project - elm incorporates both a sound type system and FRP.
This has nothing to do with time. It was a decision not to support it.
sure part of the decision is that you can't really soundly type (in a developer sanity preserving way) across a cluster that runs multiple versions of software (which is a real use case that the authors absolutely needed to support as part of the core business). but they let dialyzer in to the core so it's not like the team was actively hostile to typing.
These are some weird sentences thrown into this thread.
What you are describing is a runtime concern that has nothing to do with types.
These issues are neither amplified nor alleviated by using types.
Okay? But "the features you need would have taken effort to implement, so we didn't implement them" is not a very good sales pitch when you're trying to convince me to use your tool to do my job.
ok. don't use it then. but be aware: your attitude is why things get stuck in (sometimes really awful) local minima in tech.
Any tool that justifies the choice not to implement an important and highly-requested feature with "effort is a finite resource" alone is not viable for serious development work. It's not prioritizing, it's a refusal to prioritize.
you probably shouldn't bulldoze into a situation with assertions like you've made with such a limited grasp of the history at play.
Seems a bit strange to posit fault tolerance as an alternative to a type system. Personally, I view type systems as a bonus to DX more than something strictly designed to prevent errors
It's in line with the erlang philosophy of letting things crash trivially and restart instantly. Due to the universal immutability, starting a new process from a given state in Erlang/Elixir is nearly instantaneous and has extremely little overhead as they are not OS threads, they are BEAM VM threads.
Very opposite the Go model, btw.
Letting you wrong computations crash does not make them right.
LOL. This only makes sense if you can know all the ways your code will fail... which you cannot.
Erlang/Elixir's approach is to simply say, "It's gonna fail no matter how many precautions we take, so let's optimize for recovery."
Turns out, this works fantastically in both cellphone signaling, which is where OTP originated, as well as with webserving, where it is perfectly suited.
I don't know who are arguing with? Everyone loves the otp.
It just does not catch logics errors.
whether that matters or not depends on whether the logic error occurs because of a rare combination of events or as a result of a certain state and whether that state remains after recovery. if there is for example a logic error that causes the app to crash after say 10 minutes of runtime, or eg. at a certain message size, then a recovery will reset the runtime and it will work again. it will of course invariably fail again after another 10 minutes or when the same message is resent, because it is a logic error, and logic dictates that the error won't go away no matter how often you restart, but it will work in the meantime.
in other words, any error that doesn't occur right at start can be recovered from at least for all those operations that do not depend on that error being fixed.
This sound like a wild and very contrived argument.
Both because that memory leaks are normal is types languages - and does usually not matter in most serious applications - and because this class of errors is usually not what types catch.
Types have value when you 1) refactor and 2) have multiple people working on a code base.
The error you see when you don't have types is something like a BadArityError.
To restart and fail again? How does that help with logic errors caused by wrong type objects?
It doesn't prevent the error, but it also won't take down your server when malicious users (or just lots of normal users) start to bang on that input with the problem, and your non-BEAM VM pool starts to run out of available preloaded stacks... You get a new Erlang process in well under a millisecond on modern hardware
It WILL log the error, with a stacktrace, so you have that going for you
Note that even with typing, you cannot avoid all runtime errors
Also note that this tech was first battle-tested on cellphone networks, which are stellar on the reliability front
Depends on the error. Lets say it is an error that happens once every 1 million users.
Tbh, the strongly typed and dynamically typed combination seems like the worst option.
You get zero help and punished hard for failing.
Nope, getting a TypeError on "1"+2 is not being "punished". That's way better than getting malformed data that you weren't expecting which keeps the system "working" until an error happens somewhere else, later, where it's more confusing.
OpenTelemetry.js did this. Being written in typescript they wrongly believed they didn’t need to check the data type for user-supplied numbers. Yeah so my production data started having dropouts because somewhere we incremented by “2” instead of 2, and then OTLP choked on 100% of the data from that process because one stat out of thousands was not to its liking and had a three thousand digit ‘number’ in it.
I never did track down the last spot where we screwed that up. This was a system we shifted from statsd, so the offending callers were either working by accident or only killing some data points for one stat and nobody noticed.
So then OpenTelemetry.js had to start sanitizing its inputs and not assuming the compiler should catch it. I still think it odd that something called “.js” was actually “.ts” under the hood.
Not getting an error on "1" + 2 is very bad if that's not what you wanted to do. Agreed.
Getting an error on "Value: " + 2 is very annoying if that's what you wanted to do.
The solution here is Static typing, not Strong/Weak typing.
how so? most dynamically typed languages are also strongly typed. that includes python, ruby, common lisp, smalltalk... if it was the worst option, this would not be the case.
A casual look at the history of basically anything will tell you that the best option isn't necessarily always the one that succeeds.
sure, but when the majority of popular languages use that paradigm then it surely can't be the worst option either. what is it that makes it a bad combination?
Please, smalltalk and common lisp don't qualify as popular languages.
I don't want to look at TIOBE, so let's look at the stack overflow survey from 2024. https://survey.stackoverflow.co/2024/technology#admired-and-...
Strong + Static: TypeScript, Java, C#, C++, Go, Rust, Kotlin, Dart, Swift, Visual Basic, Scala
Weak + Static: C
Strong + Dynamic: Python, Lua, Ruby, R, GDScript(*)
Weak + Dynamic: JavaScript, PHP, Matlab, Perl
At this point I'm reaching into the low percentages. I think it's pretty clear that Strongly + Statically typed languages are massively over-represented on the list.
Both Strongly and Weakly Dynamically typed languages are similarly represented.
Note: I'm open to editing the comment to move languages from and to various categories. I haven't used many of them, so correct me if I'm wrong.
smalltalk and common lisp don't qualify as popular languages
not anymore. they were very popular in the industry at one point. very few other languages have so many independent implementations as smalltalk and lisp. a testament to their wide spread use in the past.
Strong + Static: TypeScript; Weak + Dynamic: JavaScript
that doesn't make sense. typescript is javascript with types, it can't be both strong and weak at the same time.
but i believe we have a different definition of weak. just because javascript, php and perl have some implicit type conversions doesn't make them weakly typed. i believe it takes more than that. (in particular that you can't tell the type by looking at a value, and that you can use a value as one or another type without any conversion at all)
C is weakly typed, it was always a major criticism, C++ too i think (less sure about that).
once you correct for that you will notice that all languages in the strong and static category are less than 30 years old and many are much younger. (java being the oldest. but there are older ones like pike which is also strong and static and goes back to 1991)
the strong and dynamic category goes back at least a decade more. (if you include smalltalk and lisp)
what this does show is that static typing has experienced a renaissance in the last two decades, and also the worst is really using any form of weak typing.
i still don't get what makes strong and dynamic a bad combination, other than it's bad because it is not static.
I mean, if you define weak like that, then yeah. But also, what languages are you left with? Assembly? Then again, it does fit with your definition of popular being popular 45 years ago. Tbh, I'm not sure if smalltalk was ever even popular. It was certainly influential, but popular?
I know that there are discussion about what strong vs weak even means, but I think most people would place the weak distinction way above yours on a possible weak-strong spectrum.
C can certainly be argued to be weak. My understanding is that it's mostly due to pointers (and void* especially). C++ is much better in this regard. I mostly just did not want to add a Weak + Static category just for one language.
Well, now that you've defined Strong to also include all of the languages I consider Weak, then yeah, no issues at all.
definitions are hard. but i am mostly concerned to make sure we are talking about the same thing, regardless of what that thing is called. i do accept and agree that javascript, php and perl may be considered weaker than python or ruby. but to which degree may be a matter of taste. to me they are still strongly typed for the most part. (and let's not get into the definition of static, that's another can of worms)
but the interesting question is really the one posed at the beginning. what makes strong but dynamic a bad combination?
i think we agree that weak is bad. implicit type conversions like 1+"2" range from the annoying to problematic and dangerous. if we eliminate weak that only leaves strong and static vs strong and dynamic.
i agree that strong and static is better in most cases, type declarations help, and pike the language i use the most myself which is somewhere between python and go, has powerful types that are a joy to work with, but for comparison in typescript types come across as more annoying (in part because they are somewhat optional, and because they get lost at runtime, so they don't help as much as in truly typed languages) but strong and dynamic has shown to be a solid combination, especially with python and ruby. so i don't feel the combination is as bad as you seem to suggest.
> smalltalk and common lisp don't qualify as popular languages.
Sure, Smalltalk isn't, but Lisp is a different story. In this context I assume we all mean to say "Lisp" and not "Common Lisp" specifically.
Lisp (as the entire family of PLs) is quite massively popular.
Standard rankings have major blind spots for Lisp measurement, they miss things like, for example, Emacs Lisp is everywhere. There's tons of Elisp on GitHub alone, and let me remind you, it's not a "general-purpose" language, its sole function is to be used to configure a text editor and there's mind-boggling amount of it out there. AutoLISP is heavily used in CAD/engineering but rarely discussed online. Many Lisp codebases are proprietary/internal. Also, dialect fragmentation artificially deflates numbers when measured separately - many rankings consider them different languages.
If you count all Lisp dialects together and include: Emacs Lisp codebases, AutoLISP scripts in engineering, Research/academic usage, Embedded Lisps in applications, Clojure on JVM and other platforms - babashka scripts, Flutter apps, Clojurescript web apps, etc;
...Lisp would likely rank much higher than typical surveys suggest - possibly in the top ten by actual lines of code in active use.
nah you just get log lines. crash is not as bad as you think it is.
I mean, it is a kind of a bug that is easy to prevent with a static type checking, but also one that will always (or almost always) get triggered.
Log lines are whatever, but a system that goes into a crash loop or fails on most requests isn't great.
Maybe try Gleam? 80% of the goodies of Elixir is the BEAM anyway and you get that in Gleam too.
> Maybe I'm just wrong
Yes you are. First of all there isn't such a thing as "strict typing", types are either static/dynamic and/or strong/weak. I suppose you meant Elixir has no static types. It is however a strongly typed language.
And just like it usually happens, static typing enthusiasts often miss several key insights when confronting dynamically typed languages like Clojure or Elixir (which was inspired by ideas implemented in Clojure).
It's not simply "white" and "black", just like everything else in the natural world.
You have to address:
- Runtime flexibility vs. compile-time safety trade-offs — like most things, things have a price to it, nothing is free.
- Different error handling philosophies. Sometimes, designing systems that gracefully handle and recover from runtime failures makes far more resilient software.
- Expressiveness benefits. Dynamic typing often enables more concise, polymorphic code.
- Testing culture differences. Dynamic languages often foster stronger testing practices as comprehensive test suites often provide confidence comparable to and even exceeding static type checking.
- Metaprogramming power. Macros and runtime introspection enable powerful abstractions that can be difficult in statically typed languages.
- Gradual typing possibilities. There are things you can do in Clojure spec that are far more difficult to achieve even in systems like Liquid Haskell or other advanced static type systems.
The bottom line: There are only two absolutely guaranteed ways to build bug-free, resilient, maintainable software. Two. And they are not static vs. dynamic typing. Two ways. Thing is - we humans have yet to discover either of those two.
You act like OP has never experienced dynamic type programming.
They clearly said they "can't go back to" it, meaning they've experienced both, are aware of the trade-offs, and have decided they prefer static types.
> Gradual typing possibilities. There are things you can do in Clojure spec that are far more difficult to achieve even in systems like Liquid Haskell or other advanced static type systems.
That's great for clojure and python and PHP, but we're not talking about them.
You act as if I said anything about anyone's experience. "they prefer static types" can mean a whole lot of things - there's type inference, soundness, turing-completeness, type classes, GADTs, higher-kinded types, dependent types, gradual typing, structural vs nominal typing, variance annotations, type-level programming, refinement types, linear types, effect systems, row polymorphism, and countless other dimensions along which type systems vary in their expressiveness, guarantees, and ergonomics.
Dynamic typing also varies - there's type introspection, runtime type modification aka monkey patching, different type checking strategies - duck typing & protocol checking, lazy & eager, contracts, guards and pattern matching; object models for single & multiple dispatch, method resolution order, delegation & inheritance, mixins, traits, inheritance chains, metaprogramming: reflection, code generation, proxies, metacircular evaluation, homoiconicity; there are memory and performance strategies: JIT, inline caching, hidden classes/maps; there are error handling ways, interoperability - FFI type marshaling, type hinting, etc. etc.
Like I said already - things aren't that simple, there isn't "yes" or "no" answer to this. "Preferring" only static typing or choosing solely dynamic typing is like insisting on using only a hammer or only a screwdriver to build a house. Different tasks call for different tools, and skilled developers know when to reach for each one. Static typing gives you the safety net and blueprints for large-scale construction, while dynamic typing offers the flexibility to quickly prototype and adapt on the fly. The best builders keep both in their toolbox and choose based on what they're building, not ideology.
In that sense, the OP is wrong - you can't judge pretty much any programming language solely based on one specific aspect of that PL, one has to try the "holistic" experience and decide if that PL is good for them, for their team and for the project(s) they're building.
Runtime flexibility is not restricted to dynamically typed languages, it just happens to be less available in some of the popular statically typed languages. Error handling, expressiveness, testing culture, meta-programming and gradual typing have nothing to do with static vs dynamic typing. The main "advantage" of dynamically typed languages is that you can start writing code now and not thing about it too much. Then you discover all the problems at runtime...forever. Statically typed languages force you to think about what you are doing in advance a lot more which can help you avoid some structural issues. Then when you do refactor computer helps you find all the places where you need to change things. Dynamically typed languages force you to write more tests that are not required in statically typed languages and that might prompt you to write other tests but if also increases the chance you just give up when you start refactoring. Finally, after some time has passed and few updates have been applied to the language and libraries, you may not have a working project anymore. With statically typed languages you can usually find and fix all the compile errors and have the fully working project again. With dynamically typed languages, you will never know until you explore every line of code, which will usually happen at runtime and on the client computer.
i see things like that written almost on the daily but i've never seen it come to pass.
this is anecdotal but i've worked professionally in ruby and clojure and it was a pretty good experience. java/kotlin/scala made me wish i could go back to dynamic land...
these days i'm in a rust shop but i keep clojure for all my scripts/small programs needs, one day i intend to go back to some kind of lisp full time though.
Sure you're right on most of this, but allow me a slight pushback here. I am sorry, I am inclined to use Clojure/Lisp in my examples, but only because of its recency in my toolbelt, I could probably come up with similar Elexir examples, but I lack intimate familiarity with it.
- Dynamic languages can harbor bugs that only surface in production, sometimes in rarely-executed code paths, yes. However, some dynamically typed languages do offer various tools to mitigate that. For example, take Clojurescript - dynamically/strongly typed language and let's compare it with Typescript. Type safety of compiled Typescript completely evaporates at runtime - type annotations are gone, leaving you open to potential type mismatches at API boundaries. There's no protection against other JS code that doesn't respect your types. In comparison, Clojurescript retains its strong typing guarantees at runtime. This is why many TS projects end up adding runtime validation libraries (like Zod or io-ts) to get back some of that runtime safety - essentially manually adding what CLJS provides more naturally. If you add Malli or Spec to that, then you can express constraints that would make Typescript's type system look primitive - simple things like "The end-date must be after start-date" would make you write some boilerplate - in CLjS it's a simple two-liner.
- Static type systems absolutely shine for refactoring assistance, that's true. However, structural editing in Lisp is a powerful refactoring tool that offers different advantages than static typing. I'm sorry once again for changing the goalposts - I just can't speak specifically for Elixir on this point. Structural editing guarantees syntactic correctness, gives you semantic-preserving transformations, allows fearless large-scale restructuring. You can even easily write refactoring functions that manipulate your codebase programmatically.
- Yes, static typing does encourage (or require) more deliberate API design and data modeling early on, which can prevent architectural mistakes. On the other hand many dynamically typed systems allow you to prototype and build much more rapidly.
- Long-term maintenance, sure, I'll give a point to statically typed systems here, but honestly, some dynamically typed languages are really, really good in that aspect. Not every single dynamic language is doomed to "write once, debug forever" characterization. Emacs is a great example - some code in it is from 1980s and it still runs perfectly today - there's almost legendary backward compatibility.
Pragmatically speaking, from my long-term experience of writing code in various programming languages, the outcome often depends not on technical things but cultural factors. A team working with an incredibly flexible and sophisticated static type system can sometimes create horrifically complex, unmaintainable codebases and the opposite is equally true. There's just not enough irrefutable proof either way for granting any tactical or strategic advantage in a general sense. And I'm afraid there will never be any and we'll all be doomed to succumb to endless debates on this topic.
> The bottom line: There are only two absolutely guaranteed ways to build bug-free, resilient, maintainable software. Two. And they are not static vs. dynamic typing. Two ways. Thing is - we humans have yet to discover either of those two.
That's true but some languages don't let you ship code to prod that multiplies files by 9, or that subtracts squids from apricots
Elixir won't allow you to do that:
Documentation is full of type information:https://hexdocs.pm/elixir/Enum.html#types
I think their point is that Elixir lets you write
It won't raise an exception or give you a warning while compiling it (tested with 1.18.4). Even adding above its definition doesn't do anything.> that multiplies files by 9, or that subtracts squids from apricots
I don't understand why when someone mentions the word "dynamic", programmers automatically think javascript, php, bash or awk. Some dynamically typed PLs have advanced type systems. Please stop fetishizing over one-time 'uncaught NPE in production' PTSD and acting as if refusing to use a statically typed PL means we're all gonna die.
A funny thing is I once had a type bug while coding elixir, that bash or perl would've prevented, but rust or haskell wouldn't have caught. I forgot to convert some strings to numbers and sorted them, so they were wrongly sorted by string order rather than numerical order.
In haskell (typeclasses), rust (traits), and elixir comparison is polymorphic so code you write intending to work on numbers will run but give a wrong output when passed strings. In perl and bash < is just numeric comparison, you need to use a different operator to compare strings.
In the case of comparison elixir is more polymorphic than even python and ruby, as at least in those languages if you do 3 < "a" you get a runtime error, but in general elixir is less polymorphic, ie + just works on numbers, not also on strings and lists and Dates and other objects like python or js.
I also experienced more type errors in clojure compared to common lisp, as clojure code is much more generic by default. Of course noone would want to code in rust without traits, obviously there are tradeoffs here, as you're one of the minority in this thread recognizing. There is one axis where the more bugs a type system can catch the less expressive and generic code can be. Then another axis where advanced type systems with stuff like GADT can type check some expressive code, but at the cost of increasing complexity. You can spend a lot more time trying to understand a codebase doing advanced typesystem stuff than it would take to just fix the occasional runtime error without it.
A lot of people in this thread are promoting gleam as if its strictly better than elixir because statically typed, when that just means they chose a different set of tradeoffs. Gleam can never have a web framework like Phoenix and Ash in elixir, as they've rejected metaprogramming and even traits/typeclasses.
That comment was specifically engendered by Python trauma
Not directly, it wasn’t:
You have to go to some length to get Python to mix types so badly.Won't prevent you from shipping this in prod. The stack trace you shown only appearing when you execute the code.
Or run mypy etc., because you care about your code.
Tests will, however.
Sure but that's not what we were talking about. Plus I don't need to add tests like this in my code for it to be valid once compiled
> specifically engendered by Python trauma
Well, yes, Python can sure feel pretty fucking awkward from both perspectives. It started as fully dynamic, then added type hints, but that's not the main problem with it, in my opinion, the problem that you're still passing around opaque objects, not transparent data.
Compare it with Clojure (and to certain extent Elixir as well). From their view, static typing often feels like wearing a suit of armor to do yoga - it protects against the wrong things while making the important movements harder.
- Most bugs aren't type errors - they're logic errors
- Data is just data - maps, vectors, sets - not opaque objects
- You can literally see your data structure: {:name "Alice" :age 30}
- The interesting constraints (like "end-date > start-date") are semantic, not structural and most static type systems excel at structural checking but struggle with semantic rules - e.g., "Is this user authorized to perform this action?" is nearly impossible to verify with static type systems.
What static types typically struggle with:
- Business rules and invariants
- Relationships between values
- Runtime-dependent constraints
- The actual "correctness" that matters
Static type systems end up creating complex type hierarchies to model what Clojure does with simple predicates. You need dependent types or refinement types to express what clojure.spec handles naturally.
Elixir also uses transparent data structures - maps, tuples, lists, and structs are just maps. It has powerful pattern matching machinery over type hierarchies - you match on shape, not class. Elixir thinks in terms of messages between processes and type safety matters less when processes are isolated.
Python's type hints do help with IDE support and catching basic errors, yet, they don't help with the semantic constraints that matter. They add ceremony without data transparency. You still need runtime validation for real invariants.
So Python gets some static analysis benefits but never gains a truly powerful type system like Haskell's, while also never getting "it's just data" simplicity. So yes, in that sense, Python kinda gets "meh" from both camps.
Average coders die with anything a little bit more complex. Adding an additional, unnecessary layer of problems won’t help with that to say the least.
I'm not sure what you're saying, but just in case if you're implying that choosing to use something like Clojure or Elixir adds "unnecessary layer of problems" just because they are not statically typed, let me remind you that "simplicity" is basically Clojure's middle-name. Rich Hickey made a seminal talk on simplicity, https://www.youtube.com/watch?v=SxdOUGdseq4 it's quite eye-opening and isn't really about Clojure. Every programmer should watch it, perhaps even multiple times throughout different stages of their career progression.
I don’t imply anything. I state (pun very much intended).
I cannot consider seriously anybody who thinks that programmer convenience and maintainability are different things on any level. And focusing on one doesn’t need the other.
Also this speech is academic blabla. I understand it, but there is a reason why he had to build a completely new vocabulary… because it’s not simple and easy at all. And there is a reason why there is exactly zero examples in almost the whole speech.
Because I can give you a very, very good example to contradict the whole speech: NAND gate.
Also you can code in Haskell basically with the same logic as in imperative languages (I used Clojure rarely, so I cannot say the same). So the “simplicity” is there only if you want to. But that’s true also the other way around: you can have the same “simplicity” in languages where mutability is the default. I agree that you should do immutability by default, but it’s stupid to enforce it. And he said the same thing, just it was a half sentence, because it contradicts everything what he preached: there are cases when his simplicity toolkit is the worse option.
Ruthless immutability causes less readable and maintainable code in many cases. And I state it, and I can give you an example right away (not like Hickey did): constructing complex data.
Also every time when somebody comes up with ORM and how bad it is, I just realize that they are bad coders. Yes, a lot of people don’t know how to use them. But just because it allows you to do bad things, doesn’t mean that it’s bad. You can say the same thing about everything after all. Every high level languages are slower than code in Assembly. Does that mean that every high level languages are OMG, and we should avoid them? Obviously not. You need to know when to touch lower layers directly. This is especially funny because there is a thread about that part on Reddit, because he used some vocabulary which is basically non existent, and the thread is a clear example of that people don’t even know what’s the problem with it. It’s a common knowledge that it’s bad, and they don’t know even why. For example, whoever fuck up a query through ORM, would fuck up the same way just with different syntax, like with a loop, because they clearly don’t know databases, and they definitely don’t even heard about normal forms.
And yes I state it again, using flexible type systems add unnecessary layer of problems. I also like that he mentioned Haskell, because it makes it clear, that his speech is completely orthogonal to the discussion here.
There is no hard YES or NO, when it comes to typing. It is not a religion. (but it sures feels like it sometimes)
There are really good arguments both ways.
Just use what you need or go with whatever your current project dictates. Over time you will probably feel drawn to both, for different reasons.
> Over time you will probably feel drawn to both, for different reasons
I agree 100%. At first I liked C# and Java types, but then I moved to Python and I was happy. Learning some Typescript pulled me back into the static typing camp, yet then I discovered Clojure it revealed to me how needlessly cumbersome and almost impractical TS type system felt to me in comparison. Experimenting with Haskell and looking into Rust gave me a different perspective once again. If there's a lesson I've learned, it's that my preferences at any point in life are just that - preferences that seldom represent universal truths, particularly when no definitive, unambiguous answer even exists.
That's quite the list of languages. If you're interested in types I would suggest also looking into F#. Shouldn't be tricky for someone who has already experienced C# and is open to different approaches to programming. For me F# was a revelation into what programming language typing can do for the developer.
I do know and like F#, and just like the other commenter I think I personally prefer it over some Haskell's ways. F# was my first FP language, I was so excited about it, but it was a hard sell back then to my team of charpers, so I sneaked it in by writing tests in it for an otherwise altogether C# codebase.
Too sad that the dotnet world largely still operates in csharpland and F# unfairly gets ignored even within dotnet community. I never have found a team where F# is preferred over other options, and I'd absolutely love to see what it's like. Unfortunately, F#'s hiring story is far worse than other less popular languages and even if there is anything, you most likely end up supporting other projects in C#, and honestly, even though it's a fine language by many measures, I see C# as "past experience" that I personally am not too eager to try again and do it as my daily job.
I really like the way F# (and presumably ocaml) do typing, it truly feels like the best of both worlds. Rarely do you need to actually write a type anywhere, and when you do it's because otherwise there might have been a runtime error.
Sounds a bit like crystal. Flow typing etc is so powerful.
I think a lot of people feel repulsed by dynamic typing for the same reason I used to: they wrote a lot of JS, and now they write a lot of TS. The experience of working in a JS codebase vs working in a (well-typed and maintained) TS codebase is a wide, wide gulf. I love working in TS, and I absolutely despise working in JS.
For a while I extrapolated my experience to mean “static typing is awesome and dynamic typing is horrible”, but then I started learning clojure, and my opinions have changed a lot.
There are a ton of things that make a codebase nice to work with. I think static typing raises the quality floor significantly, but it isn’t a requirement. Some other things that contribute to a good experience are
- good tests, obviously. Especially property based tests using stuff like test.check
- lack of bad tests. At work we have a very well-typed codebase, but the tests are horrible. 100 lines of mocks per 20 lines of logic. They’re brittle and don’t catch any real bugs.
- a repl!!
- other developers and managers who actually care about quality
All four of these examples seem pretty easy to find in the clojure world. Most people don’t learn clojure just to get a job, which is maybe a hidden feature of building your company with a niche language.
At the same time, I recognize that most of those examples are “skill issues”. Static typing does a good job of erasing certain skill issues. Which is great, because none of us are perfect all the time!
Exactly this. When speaking about static or dynamic type systems, you can't discuss them in isolation, you need to specify because the holistic experience of types in JS, Python, Clojure, Elixir, Haskell, Rust, etc. will differ, sometimes drastically. Leaning too much to any side is perilous; it may create a false narrative in your head about what types fundamentally mean and how they should be used.
Camping too long on either side may create wrong assumptions like that all/most problems are type problems; make you conflate implementation with concepts and make you miss the real tradeoffs; you'd start ignoring context and scale.
Static types aren't always about "safety vs. flexibility" - sometimes they're about tooling, refactoring confidence, or documentation. Dynamic types aren't always about "rapid prototyping" - sometimes they enable architectural patterns that are genuinely difficult to express statically.
One really needs to see how Rust's ownership system or Haskell's type inference offers completely different experiences, or how Clojure's emphasis on immutability changes the dynamic typing game entirely.
I wouldn’t say that static types remove the need for unit tests… but they do significantly reduce that need.
Static types and unit tests are not equivalent either. A static type check is a proof that the code is constructed in a valid way. Unit tests only verify certain input-output combinations.
Imo this complaint is really overrated: https://arrowsmithlabs.com/blog/you-might-not-need-gradual-t...
I liked the article, but I found it a bit strange that it presented pure functions as a feature of Elixir rather than as a general good practice. Surely there's nothing particularly unique about Elixir in this regard compared to other languages?
There are auxiliary language features such as pattern matching that make pure functions viable at scale.
> But honestly, I’ve always felt like this objection was overblown. I’ve got nothing against static typing; some of my best friends use statically-typed programming languages.
lol
One of the problems with strict typing is that it makes it very difficult to hot upgrade a function to a different signature.
Erlang OTP relies on being able to swap to new functions to do upgrades without downtime.
If you're trying to hot swap a function for a version with a different type signature, how was the new code going to run successfully anyway? Unless the type signature changes aren't reflecting the runtime behaviour changes?
It's a solved problem in gen server actually. Kinda. You migrate in-memory data and if something doesn't align, it restarts.
You can have a tag so pattern matching can discriminate. You can have new function parameters. You can append to the end of a data structure.
All of these would nominally be considered a type signature failure.
You can have strict typing with dynamic typing, like PHP with declare(strict_types=1);
Not just you; my standards for typing and tooling are quite high these days. Happy with C# and TypeScript, avoid Ruby and Python these days if I can.
> Am I the only one
Far from it.
I mean, lots of extremely talented and successful engineers, e.g., DHH, think strict typing is actually a negative. I think if you think strict typing is an absolute disqualifier, you should steelman the opposing side.
His "argument" for strict typing on the Lex Fridman podcast was also that it's mostly if you have "hundreds or (of?) thousands of engineers collaborating", which "strictly" puts his opinion in the bin in my case. I have absolutely, positively become more productive as a single developer due to strict typing. Parsing various kinds of binary data was enough to convince me. A.k.a. each to their own. On the whole, Elixir and BEAM seem really cool though, and there's work being done on typing, as well as the new Gleam language.
Note: I've not yet done any serious web-development, mostly command line tools, which I realise is not DHH's main focus.
I tried both and I respect different opinions about this. I feel like TS' type system makes me crazy because it's going too far. But no typing makes me anxious. I guess there is a sweet spot to find for me personally.
I prefer something like specs[1] that define a function’s signature but isn’t enforced by the compiler, instead the linter enforces them.
This is what Erlang has and it’s very convenient since once a design is fixed, I end up writing a spec to remind me what types the function expects.
[1] = https://www.erlang.org/doc/system/typespec.html
I really don't get how having to write
is better thanAnxious about what? What's your issue with dynamic typing?
Thorough tests of the behavior of your system (which should be done whether the language is dynamic or not) catch the vast, vast majority of type errors. "More runtime errors" in a well designed codebase don't mean errors for the user - it means tests catch them
Seriously.. the secret to writing great dynamic code is getting very good at testing
I come from a PHP and Python background. I can see how progressive addition of types has changed the way we deal with code. Working on a big old project without types is not even possible for me anymore. Refactoring things with types is already such a tedious task. Without it it's barely possible.
The thing is most useful for me about types is it serves as forced documentation. I look at function signature with types and know what kinds of values it accepts and what it returns.
For sure. The biggest advantages of static types I see is the better tooling + faster feedback for type errors. They're advantaegs but not that big of a deal and they're equal to the tradeoffs you're making to where it doesn't matter much
I see dynamic codebases being written differently though. We all know those tradeoffs - so conventions pop up to deal with them. A method that ends in a ? in ruby - like user.admin? - always returns a boolean. You get better at naming to make types clearer
I definitely miss the perfect automated refactorings though
I knew TS's type system went too far when I saw the 8 queens problem solved in just the type system, not the actual language. Me, I just want to get stuff done, not fight my type system.
And that was even before someone wrote DOOM in TS's type system.
Elixir and Phoenix are very underrated.
It combines the "opinionated" aspects of ruby and rails and the power of erlang. The BEAM is like no other runtime and is incredibly fun to work with and powerful once you get how to use genservers and supervision trees.
We use Elixir for Mocha, and my one issue with it (I disagree with OP on this) is that live-view is not better than React for writing consumer grade frontends. I wish Phoenix took a much stronger integration with React approach, that would finalize it as the top choice for a web stack.
My current project is using React Native (for native and web) and getting GraphQL setup was initially a pain, but having React and GraphQL subscriptions gives me enough of the "live" functionality, but without having to worry about connection issues. With gql-tada, I get fully typed experience on the front-end too.
If I didn't need native functionality, I'd probably just use the recently released `phoenix_vite`: https://github.com/LostKobrakai/phoenix_vite
Yeah it’d be nice if they had a mix task to include your js frontend of choice and it “just worked”. Many have used inertia with success. I’m taking a different approach and pairing svelte with Phoenix channels.
Something like https://github.com/mrdotb/live_react might be what you're looking for.
Any thoughts on Inertia for including React into the picture?
Yes, it’s always a surprise to me that, given how great Elixir is, it didn’t take over backend development. It seems so much better suited to doing something similar to microservices without a lot of the overhead you’d think people would love it. It always seems that fads win and projects with extremely tight concepts remain niche.
While Elixir is my current favorite language to hack in, it is very alien and downright hostile to integrating with existing systems. For example, relational database support was postgres focused for a long time (to the exclusion even of SQLite and continued inability to talk to Oracle). Then you have articles like https://dashbit.co/blog/you-may-not-need-redis-with-elixir pushing ETS over Redis. While it's a valid argument, it's not adoption-friendly.
Clojure brings about half the novelty of Elixir, runs on the JVM and still struggles to replace Java.
What’s wrong with that article?
For what it’s worth, I’ve been using Elixir professionally for a few years now and haven’t touched Redis once.
Not sure why telling people they don’t need another service is bad for adoption?
Pretty sure there has been BEAM connectivity for Oracle for at least five years. SQLite3 is one of the defaults in Phoenix and have been for a long time. I do mix phx.new curious_idea --database=sqlite3 at least once a week, it's a sub-minute effort to a mostly generated base for a prototype (with OK auth/user management) I can just throw on a VPS and show someone.
If you want an in memory store without interfacing over HTTP, that is less foreign than ETS, try Duckdbex. Mix.install or add to mix.exs, then it's two lines and you get a connection to an ephemeral database with a SQL interface. Can probably do the same with SQLite but I've never done it. If your needs are simple you can just boot a GenServer with a K-V structure as state.
Pattern matching, the capture operator and functional programming style are the really "hostile" parts, in my experience.
In my current project we use Oracle database. It’s possible and almost on par with Postgres.
Just as long as you do not need a boolean.
(I know, modern Oracle has finally fixed this, but I have Oracle 11 and 12 systems which bring me daily joy)
Is it a problem with Elixir then?
The way concurrency work in elixir compared to JS I used to view it as a potential nodejs killer.
It was never marketed that way though, and then Typescript took over which makes things even harder.
i understand, but i am not familiar with how one allocates hosts to create a cluster of beam instances across which elixir/gleam apps are running.
is there a popular pattern, perhaps as used by whatsapp, i guess?
It’s all built in at the language/runtime level and then extended with things like Horde or libcluster.
One thing the author didn't mention is how incredibly polished the primary ecosystem of documentation, standard library, and tooling is. The Elixir standard library is incredibly consistent in order to support Elixir's piping operator, such that the first argument will basically always be the information you want passed from the function before it. In comparison, I frequently have to check the docs to confirm argument order on any lesser-used function in Python, Javascript, or C#. Then there's the fact that the second-layer of standard library, the OTP inherited from Erlang, which is expansive to the point of containing most things you'd want to do on a server. The documentation, in turn, is the gold standard that I (typically negatively) compare all other language docs to. It's organized, discoverable, and covers not just the "what" but the "How" and "Why" exceptionally well, not just at the function level, but the module layer as well. Frankly, only MDN comes close. All combined, it's just an incredibly productive language.
Here's another Good News Story of Elixir adoption:
How Elixir Powers the BBC From PoC to Production at Scale - Ettore Berardi | ElixirConf EU 2025 https://www.youtube.com/watch?v=e99QDd0_C20&ab_channel=CodeS...
Thanks for sharing.
Hi! I recently tried to get into Elixir as an antidote to an acute javascript-fatigue...
To my surprise this there isn't really a good mobile story to build mobile apps for both Android and iOS with it, although it looks like it could be a great option for quick turnaround mobile apps with a web- or native frontend...
I know that there is something being worked on, eg. LiveView native: https://native.live/ , but that seems to target two entirely different frontend frameworks, one for each platform...
I started using capacitor as a wrapper for a HTML frontend, but I think I might potentially run into trouble when I'd try to move into production builds...
I think there's some space for research and maybe some nice starter packs / tutorials there... Because I think it is a big and pretty relevant market for browser-based apps, which Elixir seems to be very well suited to!
I'm grateful for any additional pointers, peace out! :)
This language and its upsides (that come from the VM) really are not for application development in this manner. I'm sure you can make it work somehow but its like using a tank to get groceries. Reliability, scalability, aren't concepts relevant to apps on mobile phones. If an app crashes to the homescreen thats fine, if your entire service goes down that's another. Would be fun if someone could prove me super wrong here but if you want to learn Erlang/Elixir/Gleam or anything BEAM I'd pick a backend project.
The continued lack of DOM access from wasm is keeping a lot of potential programming languages out of this space.
Uh, yeah, it's primarily a backend language, with any frontend stuff being either a thin layer or experimental, AFAICT. OTOH, doing a more traditional backend-heavy web app might be just the thing for JS fatigue. :)
I second the "9. What You Don’t Need to Worry About with Elixir" ; and indeed I would advice to _ignore_ some things that look like standards (kubenertes, docker, etc...) and embrace BEAM / OLTP / hot reloading, etc...
I've seen a world where we tried to ship an elixir app "as if it was a go microservice" - it does not work, does not help, and you loose a lot.
Also, I wish the author had addressed the static typing. This was my biggest pet peeve when working on a non trivial app for 5 years (Mistakes were made because actors are not familiar, and fixing those mistakes was hard because of a lack of static typing.) I wonder how the situation has changed lately with the introduction of _some_ type checking.
I've been using Elixir for about a year on a side project and I've been enjoying it more than any other backend I've used (Node, Rails and C#). I recently discovered Ash and I feel like after that initial learning curve my productivity (and code quality) has improved quite a bit.
I wish Elixir had more mindshare beside just LiveView and "real time" type functionality. Even building a GraphQL/JSON endpoint without real-time requirements, the functional nature (no side effects), pattern matching and ruby inspired syntax makes writing plain old JSON controllers a joy.
While Elixir might not have a package for every use case under the sun, the low level primitives are there.
Personally while I enjoy Elixir/Phoenix, I didn't like Ash because there's way too many keyword DSL to learn.
It's like Rails except that there's much more resources for Rails to find if you made a mistake in the DSL
Yes, the learning curve is a extremely high. It took a few false starts over time, but after the "Ash book" came out, I gave it a more serious try and it finally started to click for me.
I think it helped that at the time I was trying to build some pretty advanced filtering functionality using Ecto and was having a pretty tough time. While searching for solutions I saw a few mentions of Ash and that it could solve the problem out of the box.
After a few days of experiments, I found that it was able to do the filtering I wanted out of the box and was even more functional than what I was trying to build.
For reference, I was trying to add some tagging functionality to a resource and I wanted to be able to filter by that tag, including multiple tags. Can I do that in Ecto? Of course, but Ash provided that out of the box after modeling the resource.
So if you're comfortable with Ecto and SQL, you can safely skip over Ash?
I guess, but you'll be writing a _lot_ of code yourself, that might be hard to maintain and can become brittle overtime as requirements evolve.
As an example, I wanted to add support for adding tags to a resource, and support filtering for the resource by the tag, and I wanted to be able to do this filtering both through Elixir functions as well as GraphQL.
Can I do this with Ecto? Absolutely, but I'd have to build it all myself.
With Ash, I created a `Tag` and `Tagging` resource, adding a `many_to_many` block on my resource, marked it as public. Then I added the `AshGraphql.Resource` extension to my `Tag` resource, marked it as filterable and I was done.
Now I can filter and sort by tags, filter by where tags _don't_ exist and more. I didn't have to do anything other than model my domain, and Ash took care of the rest for me. Not only that, but it probably did a lot of things for me that I probably wouldn't have thought of, such as supporting multi-tenancy, policies and more.
It really is a lovely tool, I can't say enough good things about it.
Does it have a learning curve? Absolutely! Is it worth overcoming it? Again, absolutely!
Ah. Looks like I'll have to get the Ash book...
Chiming in to recommend it too! The policies are really good too, for instance this is one from our code base:
And what's nice is that these policies apply for both the API and the frontend code without having to do anything extra :)That is like 0.5% of what Ash helps with :)
Except that it's not like Rails in the sense that in Rails, you will eventually develop extremely difficult to debug race conditions thanks to mutability that Elixir lacks.
Source: Has worked on million-line Ruby on Rails codebase
The only thing putting me off is the lack of static typing. But I'm open to be convinced that this doesn't matter.
It doesn't matter as much as you think. I believe this is in part due to how assertive most Elixir code tends to be. [1] These assertions not only aid the LSP and can cause compiler warnings/errors, they also help LLMs just like types do.
Still, every release now contains new type system features. Next up is full type inference. [2] After that will be typed structs.
[1] José Valim giving his balanced view on type systems: https://www.youtube.com/watch?v=giYbq4HmfGA
[2] https://hexdocs.pm/elixir/main/changelog.html
Pattern matching makes up for the lack of static typing for me. Combined with guard clauses it feels even stronger than static typing.
They are working on a type system.
Fwiw, Claude 4 is really good with Elixir, including whipping up quality test suites.
Can agree with this. I have had some funny hallucinations, though, where it mixes up Elixir keywords with totally unrelated to programming things and then acts very confident that said things are in Elixir. So you just need to be a bit skeptical and double-check it. But that goes with the LLM territory anyway.
Can we say that being a functional language makes it easier for AI to understand and write cleaner code? Basically, there are no mutations of input data and I guess somehow that makes it easier for the LLMs to understand and keep a track of the input and avoid weird and fancy mutations down the call stack.
Maybe. Tidewave MCP is not perfect but helps. Also having good test coverage.
> whipping up quality test suites.
YMMV, but I think it writes fine unit tests, but really sub par functional or end to end tests that need to check business logic. I think that's just a hard case for LLMS and not an elixir issue though.
Ya, it one shotted a Server driven ui app using elixir backend, expo with phoenix channels. Was impressed.
It's not free.
Define free.
I really like Elixir. We’re a small team of a few.
We work with series of timespans a lot in our domain (ag tech irrigation automation), and I needed to write an algorithm that creates the time based “diff” comparison between two or more span series.
I’ve written this code a few times already in Swift (iOS app), Kotlin (Android app), and Python (firmware). Loop based and tricky around the edge cases.
Doing it in Elixir with pattern based recursion was a pure joy. Every single test past the first time I ran it.
I don’t love the Elixir syntax (it’s noise to signal ratio isn’t as good as say, Python); I don’t love the lack of a good IDE experience that really leverages Elixirs model. But I do love the mental computation model of Elixir, and the very simple set of rules, vs some of the other languages I have to work in.
I've been wanting to learn Elixir for a long time but is it worth learning it without knowing Erlang first? I'm not against learning Erlang but just curious if Erlang is a good thing to know before tackling Elixir.
Erlang is definitely worth learning but definitely not required by Elixir.
Learning the concepts that embody Erlang such as tail recursion and function matching, make Erlang worth learning. Erlang is also a special mix of Prolog and Lisp.
To add to this, Erlang is a very simple language that you can learn in just a few days. I don't know Elixir but I assume that, as is the case with Erlang, the more difficult thing to learn is OTP and not the language itself.
For me Erlang was worth learning because it's so interestingly different to many other languages because of its Prolog roots.
I only learned Elixir because the company I currently work for is an Elixir shop. I've basically ignored Erlang since I started here, other than the occasional library being Erlang.
I don't think it's really impeded my ability to learn or use Elixir. But I could also see how learning it and the underpinnings for Elixir could aid understanding too.
Yes, it is worth it to learn Elixir without learning Erlang, absolutely.
I consider myself expert-level at Elixir and did not learn Erlang first. Couldn't write a single line of Erlang today unaided if I tried.
I picked up Joe's Erlang book years after out of pure joy/curiosity.
Especially with LLMs, totally unnecessary.
You don't need to learn Erlang first.
It is absolutely 100% _not_ necessary to learn any Erlang at all before learning Elixir. I've been developing with Elixir for 5 years and still have never written a line of Erlang.
You don't need to learn OTP at first either — it'll just slow you down and confuse you. Learn Elixir syntax and semantics, learn how to build a Phoenix app or whatever, then dive into OTP once you're comfortable with the basics.
We've been running Elixir in production for 5+ years and most of our team only know some very basic erlang data structures for working with the :dbg module on live systems.
Erlang knowledge is not needed for building products with Elixir at all unless you want to go very in-depth.
~5 year pro elixir here, various systems in production, I don't know any erlang.
You can get very very far in Elixir without even knowing about an acronym called OTP.
Maybe not Erlang the language, but it’s useful to know its "philosophy" and what the BEAM is all about.
Erlang is just fun to learn anyway even if you never use it. Fascinating language and history.
I built a whole startup in elixir from 0 to 1000+ active subscriptions. I don't know a lick of erlang.
That's pretty cool - what is it if you don't mind talking about it? How do you feel Elixir made it possible or easier. Or is it just something you happened to choose and you could have used Node or Rails or whatever else.
I was a nodejs engineerfor 7 years previously and had a lot of experience it. if you're building a backend, unless you're relying on a specific library or building a microservice, I think elixir/phoenix is a way better stack. being functional and having a pass by value by default, you avoid whole classes of errors you have to learn to look out for in node. While there was some initual challenge setting up autodiscover with libcluster, it means we were able to get away with not setting up a message queue or pubsub system or websocket infrasturcture since all that came out of the box. Additionally, creating services is as easy as adding a controller in rails. just use Genserver and add it to your supervisor file.
TLDR: sure i could have done it in node but it would have been a LOT more work and less reliable
You do not need to know much, if any, Erlang to be productive in Elixir. Some libraries you might call will be written in Erlang, but those tend to have been around long enough that you don't need to look inside. Being able to read the Erlang docs can be helpful, because the OTP has a ton of helpful functions, but that's mostly just learning what Erlang calls its types.
I have never done anything serious with it, because I don't have any use case, it is not a programming language that either our IT, nor customers want running on their servers.
Only thing that always gets overseen in language discussions about which one is best, is that most companies pick languages based on ecosystems and products they buy/adopt, not pick a programming language from a catalog and then go looking for problems to solve with that language.
Unless of course they are a startup trying to get hold of a new domain, many times creating the need for others to adopt a specific programming language, when their product gains enough market share, thus we are back into how (the other) companies pick programming languages.
That is how we end with languages that maybe should never have been mainstream, a lucky product, killer application, market adoption happens, people want to learn the language to get employed, and the adoption circle goes on, thus whatever misconceptions there are matter very little for most programming languages, once they pass the adoption threshold.
There's a real uphill battle for adoption. Can't use it because it's not popular enough and there aren't enough experienced devs. Its not more popular and people don't have that experience because it's not used as much.
Half (if not more) of the things my company is working on right now would just not be a thing if we used Elixir. But instead, we're one of millions of companies re-inventing solutions to the same distributed computing problems using Node & AWS in a less optimal and worse-tested way. Such is life.
Indeed, and hence why for example while I would rather use Smalltalk, Prolog, Lisp or Standard ML, I have to also contend myself with their influences on programming languages and tools that we are actually allowed to use.
AI generated images makes me think that an article was also generated with AI
I’ve been working with Elixir professionally for the past 7 or 8 years, and I have to say, phoenix and are great, but it’s the repl I miss the most when I’m building in other languages. The ability to interact with a system, ask questions, try code, is crucial when I’m debugging
Could you have at least rewritten some of the obvious AI stuff? "it's not X - it's Y" appears about five times in the first minute of reading, at which point I gave up (after all, I could just ask ChatGPT to generate the article myself)
Some don't use it because the performance on anything other than IO is just bad. This isn't just because its "not compiled", but because it has a scheduler taking up cycles and it enforces immutability, when can be brutal for some tasks when mutability can really speed things up.
In some cases it might be worth the effort to extract such performance hotspots out of the BEAM and access them over port, NIF or socket.
I'm not a fan of FFI stuff because I'm a simpleton, but have had an easy time incorporating both Python and Java in Elixir systems.
if the author is reading this a minor edit should be that whatsapp uses erlang, not elixir.
Yeah, that’s a fair point.
I just started learning Elixir recently and I'm honestly loving it. Pattern matching is awesome and how it approaches concurrency and async work was so easy to wrap my head around. Pragmatic Studios has a great tutorial.
I’m skeptical of this claim, where is he getting it from?
“Elixir’s foundations in functional programming…make it easier for large language models to reason about, generate, and test code. LLMs struggle with imperative codebases full of side effects, hidden state, and indirection…”
It seems a larger factor in LLM performance on a given language is the amount of code available to train on.
I've found (specifically using Idris 2, but any functional language with some typing should work) LLM's to write better code in these restrictive languages simply because there are significantly fewer ways to screw up that are possible without causing an error upfront.
In fact, I would even go so far as to say that LLM code assistance may cause a boost in interest in those languages.
If you structure your prompt around small, stateless functions with explicit inputs/output, answers may look cleaner, but that advantage is not at the language level. You can do the same in TypeScript et al and get the same results.
I don’t doubt that anecdotally you’ve had favorable results. However, I’m not aware of any research that backs up this claim. Or forget research - I’m not aware of any simple examples / prompts that would show it in a reproducible way across different LLMs.
Corpus size tends to dominate performance.
> I’m not aware of any research that backs up this claim
These things are literally days old. Claude 4, which is arguably the first truly useful LLM code assistant, released in May. Scientific research proceeds at a glacial pace. I'm just speaking from anecdotal experience. It may be a perceptual illusion, or it may be a real thing. Just my data point.
One could deduce that restrictive languages would naturally result in fewer runtime bugs produced by LLM's since they do the exact same thing for people. For example, Elm is literally designed to produce NO runtime errors, so coding Elm in an LLM (which I haven't done) would ostensibly result in almost all errors being caught upfront.
This is not to say that other types of logic errors, redundancy, etc. wouldn't slip through without human intervention.
Elixir's syntax is very intimidating. We maintain a fork of "bors-ng", I'd very much like to hack around a fix or two, but just stare at the code in awe.
What part of the syntax is intimidating? To my mind, it's not all that dissimilar from e.g. Python, which is not a language about which people express the same feeling.
Structure and control flow feels very Python/Ruby-ish, however, when you get into the depths of pattern matching and binary deconstruction or even macros, Elixir syntax can become somewhat messy. However, the same concepts, once understood, are extremely powerful for parsing or protocol handling.
Talking about stuff like this:
I didn't say "part of syntax is intimidating," to me all of it is.
Right now I stare at the sibling comment and just don't grasp what's going on.
Have you learned the language? Expecting to know what’s going on without having learned the syntax is a bit silly
Biggest issue is lack of job opportunities with Elixir
I have a ton of respect for José Valim and the Elixir core team, I have to say: Elixir just doesn’t mesh well with the kind of infrastructure tooling that’s become standard today. The ecosystem has been growing impressively and there’s a lot to admire, but its philosophy often feels at odds with containerized, Kubernetes-based deployments.
Elixir promotes a "do it all in one place" model—concurrency, distribution, fault tolerance—which can be powerful, but when you try to shoehorn that into a world built around ephemeral containers and orchestration, it starts to crack. The abstractions don’t always translate cleanly.
This opinion comes from experience: we’ve been migrating a fairly complex Elixir codebase to Go. It’s a language our team knows well and scales reliably in modern infra. At the end of the day, don’t get too attached to any language. Choose what aligns with your team’s strengths and your production reality.
If you can't get Elixir to work well in k8s, you're simply doing it wrong. Yeah you can build a lot of what k8s offers on the BEAM on a bare server but you don't have to at all. Elixir offers modern telemetry that works really well with pretty much any monitoring tool, and give you a lot of introspection into the internals of the VM if you need it. "Let it fail" works just fine in k8s, you can run a supervision tree in a container and have it manage process restarts internally just fine, its just an added layer of fault tolerance. Sure, you can't easily have long running stateful processes if you're doing a lot of blue-green deployments, but you probably don't need to do that most of the time.
If you don't know Elixir and the BEAM well, of course you're going to have a bad time. That's true of any language.
phoenix live view is effectively built around the assumption that the server process never dies and never restarts. its a very dubious model for a production deployment.
> what happens when the server restarts / connection is lost / server dies?
> you lose all of the current client state but you can work around this by persisting all the client state somewhere.
> oh, so why am i using live view again?
> phoenix live view is effectively built around the assumption that the server process never dies and never restarts.
Not exactly, it's built to hold state in memory by default but doesn't assume how you want to handle deploys or server restarts. There's a built in restore mechanism for forms and it's trivial to shuffle state off to either the client/redis/your db[1]. You'd have the same problem if you were storing all your state in memory for any web application regardless of your library choice. Or you conversely have the problem that refreshing the page trashes client state.
So there are two thinks here, you don't have to use live_view to use elixir or phoenix, and if you do you just need to actually think about how you're solving problems. The state can get trashed anywhere for any number of reasons. Tossing on the client and forgetting about it just moves the problem.
[1] https://hexdocs.pm/phoenix_live_view/deployments.html
> You'd have the same problem if you were storing all your state in memory for any web application regardless of your library choice.
But that's the thing - traditional server-side web applications don't do this. The the stateless request/response cycle of traditional server-rendered apps is a _huge_ advantage from a system design standpoint. State is bad. State is hard to manage correctly over time. Elixir makes it possible to manage this in-memory state relationship better than other languages, but it's still difficult to do at scale regardless.
LiveView turns stateless web applications into stateful web applications, and this is a problem most folks aren't considering when they see developer experience improvements the LiveView project claims. This is _the_ specific tradeoff that LiveView makes, and I wish folks wouldn't handwave it away as if it were trivial to manage. It's not. It's a fundamentally different client/server architecture.
Source/disclaimer: I work at a large company with a large LiveView deployment, we have spent a ton of time and money on it, and it's a pain in the ass. I still love Elixir, I just think LiveView is oversold.
I guess my quibble is that I’ve talked to Jose and Chris about this and I don’t think they’re overselling it. The caveats are in the docs and they expect you to understand the tools.
And realistically there are cases where I’d use another tool.
the way live-view is sold is some kind of alternative to writing javascript. if you have a very rich client side application then you can easily end up with a bunch of state which would be in the clients memory but now is in the servers memory. but if its in the servers memory the data ends up being much more fragile because any failure of the client or the server means the live view state is lost. whereas if the data was just in client memory then it would only be lost if there is a problem in the browser. ideally people would write applications that are tolerant to both faults. but i think in practice live-view practitioners just ignore the problem and then you are left in a worse situation.
i realize there is still a dataloss problem when there is state on the client but there is a lot of simple stuff that causes problems if you are effectively reloading the page if the server disappears due to a redeploy or a crash.
for example i'm reading an email in my message client. i've scrolled half-way down the email. but now the server crashes i reconnect to live view and my scroll position when reading the email is reset.
when i look at live view i feel like its written by people that have never deployed something in production. of course this is not really true but i feel like it would be better if live-view people were more honest about the tradeoffs. its a very complicated situation and having some bad outcomes might be worth the increase in developer productivity but i feel like live-view people just ignore the bad outcomes.
also, take a cloud deployment. websockets seem to be an inherent problem in cloud deployments especially AWS. as far as i know AWS does not expose some event to a instance that is part of a load balancer that it is about to die. ideally if you have a websocket instance with a client and you realize you are scheduled to be reaped you would message the client that it needs to reconnect. then the client would reconnect to a server that would not be reaped and everything would be dandy. but AWS doesn't seem to have this functionality (or its not easy to implement!) but more importantly live view does not expose any kind of hooks so you can have 'safe' server redeployment out of the box.
I'm not sure who from the core group of developers is overselling it in the way you're claiming. Yeah, I wouldn't try to build figma or gmail with liveview, but I'd be fine building an app for a bank for example. Tools exist in a mesh of other tools and problem spaces where they may or may not be appropriate.
This isn't true. LiveView has buit-in form recovery:
https://hexdocs.pm/phoenix_live_view/form-bindings.html#reco...
it really depends on what you are doing. if you have a complex application then the automatic recovery might not be enough for a fault free user experience. i feel like live view is sold as some kind of magic where the developer does not have to write javascript and you can just implement the server side purely in elixir as you would javascript without writing to a database, or some session storage. but if you do this then you are in a worse situation than javascript when it comes to network faults, or server processes restarting.
Sure, if your a company which is fully bought into ephemeral containers running on Kubernetes then Elixir is probably not going to be a great fit for you. I have once introduced it into a company like that and eventually the same thing happened, the application got rewritten in a language that fits the paradigm better.
If I were starting a new company today though I'd probably go with Elixir, and then I simply wouldn't bother with containers, Kubernetes, and schedulers. Just run some servers and run the application on them, let them cluster, and generally lean into the advantages.
most people/companies who think they need kubernetes don't actually need it. you are not google or amazon. and with erlang/elixir that's likely even more true.
> if your a company which is fully bought into ephemeral containers running on Kubernetes then Elixir is probably not going to be a great fit for you
As a community, we have got to stop saying this stuff. It's false. Nothing about Elixir or k8s precludes using the other. Elixir applications can and do run just fine in containers and k8s deployments. In fact, they're complementary: https://dashbit.co/blog/kubernetes-and-the-erlang-vm-orchest...
Elixir has a Ruby on Rails approach which is kind of all in one. Not everyone’s cup of hot chocolate.
Erlang is low level, lightweight processes and message passing - perfect for micro-services and containerisation.
What Erlang lacks are high level web-oriented packages, i.e. markdown conversion, CSS and JavaScript packaging, REST (not quite true: cowboy is fantastic) - for which though Erlang was never intended.
However the cool thing is that you can combine both in the same project, allowing you to have high level Elixir and low-level process management in one project. This is possible because both use the same virtual machine - BEAM.
Erlang isn't really that much lower level than Elixir. The Elixir syntax is just a bit different and they've improved a few things like string handling. Processes are still processes.
We look at K8s more like "the Cloud Operating System". Many of its capabilities are more valuable for other runtimes, but that doesn't mean that Elixir is a bad fit with it.
For example, the Erlang VM clustering can make use of K8s for Service Discovery. You can do ephemeral containers and use readiness probes to create a " hand over" period where new instances can sync their data from old, about-to-be-replaced instances.
Did you do hot updates? I ser that is mention in the post, but I thought the community has walked away from it? Or at least that its mixed feelings about it?
being able to remote into the runtime, manage state and interact with internal BEAM processes is an amazing experience
That’s the BEAM and is common to Erlang, Elixir and Gleam.
So it’s not a feature specific to Elixir since the BEAM is the common virtual machine.
I'll take Elixir, thanks.
Am I the only person who is put off by Elixir by the lack of S-expression syntax?
I decided to learn Clojure for my next language.
There is Lisp Flavoured Erlang https://lfe.io/ created by Erlang co-inventor Robert Virding.
But wouldn't I be right in thinking that the Elixir ecosystem isn't interoperable from it? I guess what I'm hoping for is a Lisp Flavoured Elixir?
> Am I the only person
No, you're not alone. After learning Lisp, structural editing and REPL-driven-development, I just don't feel like needing to learn new languages no matter how powerful they seem to be. Lisps like Clojure are highly pragmatic and offer something fundamentally different from the endless parade of syntax-heavy languages that dominate the mainstream.
Once you've experienced the fluidity of paredit or parinfer, where you're editing the structure of your code rather than wrestling with textual representations, going back to manually balancing brackets, fixing indetnation and carefully placing semicolons feels like reverting to a typewriter after using a word processor. The code becomes malleable in a way that's hard to appreciate until you've lived with it.
And the REPL changes everything about how you think and work. Instead of the write-compile-run-debug cycle, you're having a conversation with your running program. You can poke at functions, test hypotheses, build up solutions incrementally, and see immediate feedback. It's exploratory programming in the truest sense - you're not just writing code, you're discovering it.
The homoiconicity - code as data - means you're working in a language that can easily reason about and transform itself. Macros aren't just text substitution; they're proper AST transformations. This gives you a kind of expressive power that most languages can't match without tremendous complexity.
So when the latest trendy language appears with its new syntax and novel features, it often feels like rearranging deck furniture. Sure, it might have nice type inference or clever concurrency primitives, but you're still stuck in the old paradigm of fighting syntax and losing the conversational flow of development.
You've tasted something closer to the pure essence of computation, and it's hard to go back.
Considering the vast majority of languages don't use s-exprs, possibly. There aren't many hardcore lispers who refuse to use anything but s-exprs.
I used Clojure and it has same goals as bigger-grammar languages, like overloaded function definitions, casting/type-hinting, method calls etc, it just achieves them in a clunkier way.
while i love s-expressions, i am not aware of any language outside the lisp ecosystem that supports it natively. are you saying that you are put off that elixir is not lisp?
i am interested in clojure, but i am put off by it using the java run time. ;-)
> i am interested in clojure, but i am put off by it using the java run time
Clojure runs not only on Java - you have Clojurescript, you have babashka and nbb, you have Clojure-Dart — if interested in building Flutter apps, you can even use Clojure with Python libs. If you need to target Lua, there's Fennel, which is similar as it's inspired by Clojure.
For me - Clojure is a hands-down best medium for data manipulation - there's just nothing better out there to explore some data - investigate APIs; sort, group, dice and slice any kind of data - CSVs, JSON, etc. Nothing else simply can match the joy how one could incrementally build up complex data transformations, it makes it incredibly productive for the "let me just quickly check this shit" scenarios that can easily turn into full analyses. REPL-driven nature of it makes it so much fun - you feel like you're playing a videogame.
I honestly wish every programmer knew at least some Clojure. I lost count of how many times I gave up on figuring out complex jq syntax and reached for Clojure instead. Or the times I'd quickly build a simple Playwright script for reproducible web-app bug trapping or quick data scraping that saved me hours of frustration and manual clicking.
There's also
Fennel -> Lua
Jank -> C++
Am I missing something or is there isn’t even an official LSP available for Elixir? For me, that looks like a red flag. From what I see, DX in VSCode is barebones.
It’s available as a VSCode extension and documented here:
https://elixir-lsp.github.io/elixir-ls/
I personally prefer Erlang because I’m closer to ideals: lightweight processes, message passing and behaviours.
Elixir abstracts that away and leaves a ruby-like language that hides much away - which good and fine.
Erlang is by no means a simple language to get one’s head around.
> Elixir abstracts that away and leaves a ruby-like language that hides much away - which good and fine.
Processes, message passing, and behaviours are all completely first class in Elixir. There's no hiding. `spawn` is `spawn`. `send` is `!`. `GenServer` is `gen_server`. `@behaviour` is `-behaviour(...)`. The entire Erlang stdlib is available directly.
We use processes, messages, and behaviours all the time in regular Elixir work.
Elixir adds a different syntax (note that I did not say better), a macro system, a protocol system, its own stdlib functionality, some better defaults, and a build tool.
It's perfectly fine and reasonable to prefer Erlang (I learned Erlang before I learned Elixir), but for the benefit of other readers, they are really not that different. The distance between Elixir and Erlang is very small. They could almost be seen as dialects.
I don't find Elixir appealing for various reasons personally. But on a related note, I'm willing to bet on Gleam big time.
> ... I'm willing to bet on Gleam big time
can you elaborate please ? thanks !
Previous discussion: https://news.ycombinator.com/item?id=44495879
I have come to the simple conclusion that yeah if a tech is great and people are not launching products internally or as startups then maybe it's time to introspect.
if using elixir supposedly gives a competitive advantage, why aren't companies using to launch new products - both existing and startups.
a lot of those things quoted in the article are present on the jvm platform or through containers.
and btw some of those companies listed have migrated away from elixir e.g brex and discord.
I’m not so sure that popularity has any kind of correlation with capability, quality, viability, etc. That has more to do with marketing, social media trends, buzzword compliance, and what’s caught the eye of the current crop of resume-driven developers and managers.
Tools like Elixir which are focused on solving problems, aren’t flashy or easy for web dev influencers (yes, they’re a thing) to tout, and have a bit of higher barrier to entry are probably at a disadvantage in this way, even if they’re actually quite good.
This is why the industry is stuck on a revolving door of JS frameworks and the n-hundreth React self-reinvention. It’s not about how good any of this actually is, it’s about how well it scratches the itch for that new car smell while also being easy to pick up and make grand declarations on social media about.
Companies _are_ launching products with it ; that you aren't hearing about it is more about communication & leverage, than about their existence.
A while back there was an effort to give more publicity on precise cases here https://elixir-lang.org/cases.html ; I think the effort is now moving to advertising the platform outside Elixir circles (e.g. more generalist conferences).
FWIW, I'm working on https://transport.data.gouv.fr, Elixir-based since 2016, the National Access Point to transportation data, which includes a business specific reverse proxy with a 3x YoY growth, with no plans to migrate :-)
3 out of 5 of all the phone calls you've ever made was managed by a box somewhere running the Erlang VM (BEAM) which Elixir gets all its concurrency and parallelism from.
And no, Discord has not moved away from Elixir. While they have adopted Rust for certain parts of their infrastructure, Elixir remains a core part of their backend, particularly for real-time communication and chat infrastructure.
maybe it's time to introspect
to learn what? that the language was not good enough? that it wasn't marketed well enough? that there was not enough community support? not enough word of mouth?
lisp users say they have a competitive advantage, as do smalltalk users. even pike at a time had a competitive advantage in that it was/is more performant than other similar languages.
some of us in the pike community kept asking ourselves why pike is not more popular. the syntax is not obscure. roxen was a killer webdev server, 10 years ahead of its time. but no takers. why? (probably a mix of lack of marketing and community support/encouragement from the financial backers, but other languages become popular without backing, so what gives?)
my point is that most times there is nothing you can do. unless you have the marketing power of sun (java) or google (go, etc), popularity of a language is mostly a case of luck and serendipity (ruby, python) or filling a unique need that no other language could (javascript, rust)
There are a large number of companies using Elixir, in small or big ways: https://elixir-companies.com/en/companies
Elixir also does not stand alone - the storied history of Erlang/BEAM in mission-critical distributed systems needs no introduction. Elixir lives within, and benefits from, that same ecosystem of libraries and tools.
So yeah I'm not sure what you believe there is to "introspect" about, nor to what end.
>Why Elixir?
Why nobody's hiring for Elixir :(
> For those I managed to confuse, “glass-to-tin” just means “front-to-back” or “from the screen to the back end”.
So like a thin mirror? Which only serves to show the viewer back to themselves? And which also consists of just two extremely simple parts, that is, two panes/sheets of uniform materials, and nothing more?
How do you even come up with this metaphor for a web-based application? It's horrible!
Sorry, it didn't land for you. It's something I've used for a while ("glass" for the screen, and "tin" for the back-end). Perhaps I'm showing my age or my Aussie slang. Thanks for reading, in any case!
(fellow Aussie, that's not a phrase I'm familiar with either)
You use the phrase twice in the article. Could I ask you to put an asterisk by the first one too?
(I came across it, stopped reading the article to Google it, couldn't find it so came to HN to search the comments and then went back to the article and saw the asterisk later on)
Ok. I’ll fix it. Thanks.
I’m genuinely surprised how much controversy this statement has caused. It’s something I’ve said many times in a professional environment and literally no one has ever picked me up on it. Makes me wonder if they were _ever_ listening …
I agree with most commenters that Gleam seems like the thing that’s going to solve a lot of the big problems I have with Elixir.
I didn’t read a lot about Nx and EXLA in the comments, so I thought I’d share my view:
In my opinion, that’s not a strong argument for Elixir, because pretty much every language has libraries like this. Rust, famously, never stops inventing these libraries (https://arewelearningyet.com/), and to illustrate my point, here are some libraries for niche(-ish) languages:
• Crystal (https://github.com/NeuraLegion/shainet)
• Haskell (https://hackage.haskell.org/package/neural)
• Ruby (https://github.com/unagiootoro/ruby-dnn)
• and many more…
They might be suitable for researchers or projects building networks from scratch, but this is already difficult with a library that plays along. For most people, it’s about fine-tuning, combining, and doing inference on existing models (and weights).
People like to criticize PyTorch, but in fairness, with it I can do useful things with recent models (which matters at the speed of things) pretty much the day they have their open source release (thanks to the transformers library). There exists an equivalent to transformers for Elixir (https://github.com/elixir-nx/bumblebee), but it doesn’t support the top 10 trending models on HuggingFace, which is a problem if you want to use them. Qwen 3, for instance, arguably the most useful open source model family at the moment, isn’t supported at all. And this is the issue all of these libraries face: they are not useful for the majority of people needing libraries like this out there.
Also, PyTorch is really well optimized, and there is a good reason that vLLM (yes, it’s not the fastest but pretty fast, supports almost everything, and is the de facto standard for open source LLM inference) is written in Python and PyTorch. Things like Flash Attention 2 are crucial for LLM inference and still hard to find. Yes, OpenXLA is technically very sophisticated, but I never got it working every time I wanted to use it, and JAX seems more comfortable if you want to use TPUs.
It’s still a very strange development that Python runs the AI revolution. Multi-node training might be a lot of fun with Elixir, but here performance (especially making sure the CPU is not stalling the GPU) is vital, which might make BEAM not an ideal choice.
There is hope though. Recently there have been some interesting developments in the Rust world (https://luminalai.com), and of course no HN comment about training and inference is complete without mentioning TinyGrad. But Elixir simply doesn’t make sense to me (for neural networks). I’m sorry.
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