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Phoenix.new – Remote AI Runtime for Phoenix

639 points by wut42 1y ago

arrowsmith 1y ago
Ah man I'm really happy to see this and excited to try it out. As an Elixir enthusiast I've been worried that Elixir would fall behind because the LLMs don't write it as well as they write bigger languages like Python/JS. So I'm really glad to see such active effort to rectify this problem. We're in safe hands.
- zorrolisto 1y ago
  Same, I watched a video from Theo where he says Next.js and Python will be the best languages because LLMs know them well, but if the model can infer, it shouldn’t be a problem.
  - rramon 1y ago
    Folks on YouTube have used Claude Code and the new Tidewave.ai MCP (for Elixir and Rails) to vibe code a live polling app in Cursor without writing a line of code. The 2hr session is on YT.
    - rahimnathwani 1y ago
      This one? https://www.youtube.com/live/V2b6QCPgFTk https://www.youtube.com/live/V2b6QCPgFTk
      - rramon 1y ago
        That's the one.
  - dingnuts 1y ago
    since models can't reason, as you just pointed out, and need examples to do anything, and the LLM companies are abusing everyone's websites with crawlers, why aren't we generating plausible looking but non working code for the crawlers to gobble, in order to poison them? I mean seriously, fuck everything about how the data is gathered for these things, and everything that your comment implies about them. The models cannot infer. The upside of my salty attitude is that hordes of vibe coders are actively doing what I just suggested -- unknowingly.
    - fragmede 1y ago
      But the models can run tools, so wouldn't they just run the code, not get the expected output, and then exclude the bad code from their training data?
      - bee_rider 1y ago
        That seems like a feedback loop that’s unlikely to exist currently. I guess if intentionally plausible but bad data became a really serious problem, the loop could be created… maybe? Although it would be necessary to attribute a bit of code output back to the training data that lead to it.
    - Imustaskforhelp 1y ago
      For what its worth, AI already has subpar data. Atleast this is what I've heard. I am not sure, but the cat is out of the box. I don't think we can do anything at this point.
  - sieabahlpark 1y ago
    [dead]
- acedTrex 1y ago
  LLMs not writing it well might be the biggest current selling point of elixir lol.
  - zupa-hu 1y ago
    Oh lol I love that angle!
  - mattbrewsbytes 1y ago
    Selling point from a developer and career perspective for sure. Its also fun to program in and at least for me made me think about solutions differently. Its a negative point for engineering leaders that are the decision makers on tech stacks as it relates to staffing needs. LLMs not writing it well, developers that know it typically needing higher compensation, a DIY approach to libraries when there aren't any or they were abandoned and haven't kept pace with deprecations/changes, etc. In the problem space of needing a web framework to build a SaaS, to an engineering leader there are a lot of other better choices on tech stack that work organizationally better (i.e. not comparing tech itself or benchmarks, comparing staffing, ecosystem, etc.) to solve web SaaS business problems. I don't know where I stand personally since I'm not at the decision maker level, just thought I'd point out the non-programmer thought process I've heard.
- throwawaymaths 1y ago
  in principle llms should do better on immutable languages since there is no risk a term will get modified by a distant function call.
  - bevr1337 1y ago
    In my experience, it's the functional part, not immutability, where they fall short. Any LLM can write immutable C# because it's easy and there's incredible amounts of training data.
    - throwawaymaths 1y ago
      good news, "immutable" is pretty much the only way that elixir is "functional" except for lambdas being first class datatypes (which is almost every language now)
- mrcwinn 1y ago
  Worried it might fall behind… further? I love LiveView, Phoenix, Elixir, OTP. But the ecosystem is a wasteland of abandoned packages. If Phoenix.new helps solve that problem, I’m all for the effort. But otherwise, the sole focus of the community leaders of Elixir should be squarely and exactly focused on creating the incentives and dynamics to grow the base. Compare, for example, Mastra in TypeScript or PydanticAI in Python. Elixir? Nothing. Not here to bash. It’s more just a disappointment because otherwise I think nothing comes close.
  - uncircle 1y ago
    All languages are a wasteland of abandoned packages, i.e. there is a very long tail of stuff no one has maintained for years. It’s all relative to the mindshare. For its size, Elixir is doing quite well.
    - erichocean 1y ago
      Most languages require maintenance. Some languages—Clojure is a good example—have packages from 10 years ago, entirely unmaintained, that still work great because no maintenance is needed.
      - arrowsmith 1y ago
        This is also true for Elixir though. A lot of "unmaintained" Elixir packages still work fine.
        sodapopcan 1y ago
        That's their point (I think, lol).
      - spiderice 1y ago
        In my experience, Elixir is very much on that end of the spectrum as well. I'm wondering if GGP just considers packages that don't have updates for 6 months as "unmaintained" or "dead" because they come from Javascript world where everything is, well... you know.
- deleted 1y ago
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- bad_haircut72 1y ago
  This is such a weird meme, Claude crushes elixir especially a fullstack app in liveview
  - heeton 1y ago
    Yea CC is great with phoenix / liveview. It’s been doing things that teach me new tricks about elixir I didn’t know yet.
    - ferfumarma 1y ago
      What's a good place to start for a completely naive but interested user?
      - heeton 1y ago
        Sorry, I only just saw this comment. Feel free to reach out (email in profile) and I’d be happy to chat.
- te_chris 1y ago
  Claude and o3 are both excellent (if a bit erratic) elixir developers.
- pawelduda 1y ago
  Claude 3.5 produces very good Elixir/Phoenix code. Haven't tried 3.7 much but I assume it's only going to get better from here
- neya 1y ago
  I use o3, it's really good with Elixir. I prefer it to Claude, but Claude does a decent job as well. If you want to take your website and business down, use ChatGPT-4o's code
- bluehatbrit 1y ago
  This last few weeks I've been going hard on LLMs to put together a new prototype project. I've exclusively been using Claude Sonnet 3.7 within Zed (via github copilot) and it' fantastic. From time to time it tries to do something a little old-school, but nothing significant really. It's very capable at spitting out entire new features, even in liveview. Over all the experience has very productive, and at least on-par with my recent work on similar sized python and nextjs applications. I think because I'm using mostly common and well understood packages it has a big leg up. I also made sure to initialise the phoenix project myself to start with so it didn't try to go off on some weird direction.
  - indigodaddy 1y ago
    Assuming you are on the $20 Zed plan? Has the 500 prompts/mo been sufficient for you? I'm debating between the Zed and Claude $20 plans-- no doubt I'd get better value from Zed's?
    - bluehatbrit 1y ago
      I'm on the free plan and have been using it via GitHub copilot instead, as the current project is a work one and they pay for that. Before this I did a small project and I hit the 50 free tier limit through Zed by the time I was about 90% done. It was a small file drop app where internal users could create upload links, share them with people who could use them to upload a file. The internal user could then download that file. So it was very basic, but it churned out a reasonable UI and all the S3 compatible integration, etc. I had to intervene a bit and obviously was reviewing everything and tweaking where needed. But I was surprised at how far I got on the 50 free prompts. It's hard to know what you really get for that prompt limit though as I probably had a much higher number of actual prompts than they were registering. It's obviously using some token calculation under the hood and it's not clear what that is. All in all I probably had about 60-70 actual prompts I ran through it. My gut says 500/mo would feel limited if I was going full "vibe" and having the LLM do basically everything for me every day. That said, this is the first LLM product I'm considering personally paying for. The integration with Zed is what wins for me over Claude, where you'd have to pay for API credits or use Claude Code. The way they highlight code changes and stuff really is nice. Bit of a brain dump, sorry about that!
- nxobject 1y ago
  Yeah – as someone who works in Common Lisp, I wish there was way to do complementary training for LLMs with existing corpora of codebases. Being able to read access documentation doesn't do much, unfortunately, to help with more general issues with correctness of output.
- victorbjorklund 1y ago
  I found them to be pretty solid for writing Elixir (not perfect but neither is it with JS) the last couple of months.
ipnon 1y ago
Chris is a hacker’s hacker.
- nixpulvis 1y ago
  A hacker's hacker who charges for closed source AI tools which work in hosted environments only. Yea, right.
  - abrookewood 1y ago
    Come on, devs need to eat. Companies need cash to employ people. After all that he has done for open source, you're complaining that something isn't free? You know you can export the code at any time right?
    - nixpulvis 1y ago
      I'm not saying he's a bad dev, just hardly fits the hacker ethos. We want things we can tinker and toy with from the inside.
martypitt 1y ago
This is really cool! And, that you did it in a few weeks is insane. How did you get VS Code embedded in your app? I'm aware of projects like Monaco, and that vscode.dev exists - so it's clearly possible - but I didn't realize it was something others could build upon? Again, kudos!
moffers 1y ago
The mental models of Elixir/OTP and AI Agents are very compatible. I’ve felt for a long time that it would be one of the best platforms for building AI agents.
- zupa-hu 1y ago
  Would you elaborate why?
rramon 1y ago
Very cool. Does it use Phoenix 7 or 8 in the video?
- arrowsmith 1y ago
  1.7 or 1.8, not 7 or 8
  - rramon 1y ago
    Thanks for correcting my typo.
- chrismccord 1y ago
  1.8rc, which is going 1.8.0 momentarily
themgt 1y ago
This looks really cool, but I gotta say I'm a bit uneasy with the apparent(?) closed-source + hosted + branding. "mix phx.new" is the way to generate a new Phoenix project, but "Phoenix.new" is closed source Fly.io product for building Phoenix projects? Feels like we're getting into a weird situation if LLM providers are publishing open source agentic coding tools and OSS web app frameworks are publishing closed source/non-BYOK agentic coding tool. I realize this may not be an official "Phoenix" project but it seems analogous to DHH releasing a closed-source/hosted "Rails.new" service.
pier25 1y ago
I'm surprised they are investing into this. I checked Phoenix recently because I was interested in LiveView and there isn't even an official AWS SDK for Elixir. Honestly doubt the AI stuff is going to move the needle much if you can't even have a dependable S3 client.
- conradfr 1y ago
  But there's two actively non-official maintained libs.
- olafura 1y ago
  What are you talking about, there has been a AWS client forever and I've never had a problem. It's not something you really need an official sdk for they are anyway often just reference because you might want different performance characteristics. https://hex.pm/packages/ex_aws https://hex.pm/packages/ex_aws https://hex.pm/packages/ex_aws_s3 https://hex.pm/packages/ex_aws_s3 I've usually not seen more than 3 or so official SDK for most services and there are a lot more programming languages than that. For example Microsoft's Graph API doesn't have an official Ruby client, they have one that sort of works.
  - Snakes3727 1y ago
    Neither of them are official which is often a non starter for some large enterprise customers.
    - pier25 1y ago
      Not only large enterprise customers. Anyone who's thinking mid or long term.
      - sysashi 1y ago
        Why do you need an official SDK to make http calls?
        1y ago
chrismccord 1y ago
Phoenix creator here. I'm happy to answer any questions about this! Also worth noting that phoenix.new is a global Elixir cluster that spans the planet. If you sign up in Australia, you get an IDE and agent placed in Sydney.
- troupo 1y ago
  I know it's early days, but here's a must-have wish list for me: - ability to run locally somehow. I have my own IDE, tools etc. Browser IDEs are definitely not something I use willingly. - ability to get all code, and deploy it myself, anywhere --- Edit: forgot to add. I like that every video in Elixir/Phoenix space is the spiritual successor to "15-minute rails blog" from 20 year ago. No marketing bullshit, just people actually using the stuff they build.
  - chrismccord 1y ago
    You can push and pull code to and from local desktop already: hamburger menu => copy git clone/copy git push. You could also have it use GitHub and do PRs for a codex/devin style workflows. Running phoenix.new itself locally isn't something we're planning, but opening the runtime for SSH access is high on our list. Then you could do remote ssh access with local vscode or whatever.
    - prophesi 1y ago
      > Running phoenix.new itself locally isn't something we're planning So no plans to open the source code?
      - chrismccord 1y ago
        confirm
      - abrookewood 1y ago
        Everyone has to eat.
nilirl 1y ago
Beautiful demo! How do I build agents like this? Does anyone know any great resources to learn how to design agents? Tool agnostic resources would be awesome.
- chrismccord 1y ago
  Thanks! Everything is overly complicated in this space. It's probably far easier than you think. The open secret is it's just a loop that POST [provider]/chat/completions. Elixir is particularly well suited here. In Elixir this is a genserver doing http posts and reacting to the token stream. The LiveView chat gets messages from the genserver agent regardless of where it is on the planet, and the agent also communicates with the phoenix channel websocket talking to the IDE machines with regular messages, again anywhere they are on the planet. I talk about this quite a bit in my ElixirConfEU talk and distill things down: https://youtu.be/ojL_VHc4gLk?si=MzQmz-vofWxWDrmo&t=1040 https://youtu.be/ojL_VHc4gLk?si=MzQmz-vofWxWDrmo&t=1040
  - nilirl 1y ago
    Wow, thank you for the link, it clarified how tool calling and "choice-making" works. It's like helping LLMs use a computer; like building an interface for it. Ok, this is enough to get me started.
CollinEMac 1y ago
I'm a little surprised by the sentiment here that LLMs don't do well with Elixir. I've had a pretty good experience using AI tools on Phoenix/Elixir side projects.
- arrowsmith 1y ago
  LLMs are definitely a lot better at Elixir than they used to be - the gap has closed somewhat. I still perceive a gap though, especially when trying to do more complicated things in Phoenix and LiveView (as opposed to just raw Elixir.) Which LLMs do you use that you find are best with Elixir/Phoenix?
  - CollinEMac 1y ago
    I haven't really used much other than Claude. I guess I should also note that I haven't really used LiveView much.
- vaer-k 1y ago
  I've only used LLMs with Elixir, so I don't have any other experience for comparison, but I've found that although Claude frequently employs the wrong approaches in Elixir, I usually know when he'll have trouble and just ask him to read pertinent documentation first. So long as he's read the manual he seems to do just fine.
krainboltgreene 1y ago
I've wasted a lot of time and energy on stuff that doesn't matter, so I can hardly judge anyone else on what they focus on, but man does it feel bad to have community leaders actively focus on building out tooling that is anti-worker. I think the only way I'd feel more conflicted is if Fly.io started building weapons systems for the military. I guess that wouldn't be shocking considering some of their lead's beliefs.
- deleted 1y ago
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- mrkurt 1y ago
  It's safe to say that if either Chris or I believed this to be anti worker, we wouldn't be working on it. He's spent the last 10+ years working on Phoenix specifically to improve the lives of the people doing the work. My experience with software development is maybe different than yours. There's a massive amount of not-yet-built software that can improve peoples' lives, even in teeny tiny ways. Like 99.999% of what should exist, doesn't. Building things faster with LLMs makes me more capable. It (so far) has not taken work away from the people I work with. It has made them more capable. We can all build better tools, and faster than we did 12 months ago. Automation is disruptive to peoples' lives. I get that. It decreases the value of some hard earned skills. Developer automation, in my life at least, has also increased the value of other peoples' skills. I don't believe it's anti worker to build more tools for builders.
  - jonator 1y ago
    Exactly. And as more software is written, the demand and possible set of softwares increase. It's really a matter of positive sum/growth mindset vs scarcity/status quo mindset.
    - hooverd 1y ago
      Maybe, but it's zero sum to the people with money. We saw wage growth in the lowest end during the Biden admin and it drove the bosses insane.
__0x01 1y ago
What LLM does Phoenix.new use?
- chrismccord 1y ago
  claude 4 sonnet as the main driver atm, and a mix of smaller models depending on the scenario
  - tptacek 1y ago
    I'm building an agent right now (or rather, extending an agent I build a few weeks ago in a couple hours) and I would love to hear more about which scenarios get assigned to which models. (I almost just asked you on company Slack but figured the answer would be more broadly interesting.)
- ethan_smith 1y ago
  Based on the blog post, Phoenix.new uses Claude 3 Opus as its underlying model, which explains its strong performance with Elixir/Phoenix codebases.
rustc 1y ago
"Sign in with fly.io" takes me to a page asking me to pay $20 but the plan details are vague - what exactly is included in "$20/mo of Built-In AI Assistance Builds, refactors, and debugs right in your IDE"?
- tptacek 1y ago
  This is a situation where we've been pushing on Chris to get this out into the world quickly, and there's a lot of packaging stuff like this that isn't fully put together yet. Thanks for calling it out! We'll get to it over the next week.
mcdirty 1y ago
This is great. I had to back out of a phoenix project and rewrite it in Django because I couldn't get good AI assistance. I'm pretty inexperienced with Elixir and Phoenix but understand the benefits enough to want to make projects in it. So this is really cool.
- causal 1y ago
  I had this experience too. Though most of my issues were with my model not necessarily with Elixir itself so much as understanding the Phoenix model, state, and CLI. Maybe even differences in versions? Wasn't always clear.
- dontlaugh 1y ago
  I find that baffling. Why not just write the Elixir yourself?
  - prophesi 1y ago
    Not just baffling, but concerning. LLM's are great for learning new languages, but terrible for outputting code you don't understand yet hope to maintain.
    - abrookewood 1y ago
      Yet, more and more people are going to be doing exactly this.
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sockboy 1y ago
Integrating AI assistance directly into an Elixir IDE could boost productivity, especially for newcomers. Excited to see how remote SSH and local workflows develop!
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gavmor 1y ago
Phoenix.new looks powerful, and I'll definitely play with it. I've been daydreaming of an agentic framework that maximally exploits BEAM. This isn't that, but maybe jido[0] is what I'm looking for. 0. https://github.com/agentjido/jido https://github.com/agentjido/jido
- fridder 1y ago
  TIL; That is a very interesting library
  - mstibbard 1y ago
    This thread on Elixir Forum is a good read if you are considering building agents with Elixir. Jido's author weighs in also. https://elixirforum.com/t/is-anyone-working-on-ai-agents-in-elixir/69989/1 https://elixirforum.com/t/is-anyone-working-on-ai-agents-in-...
johnwheeler 1y ago
Why wouldn't LLMs work as well with Elixir as python or JS? LLMs don't parse an AST.
- lawn 1y ago
  Because of the amount of Python and JS in the wild is much more than the amount of Elixir code, so the LLMs have much more data to base their answers on.
  - johnwheeler 1y ago
    Thanks
jsmo 1y ago
Hmm, just signed up to check it out but no trial just "$20/mo of Built-In AI Assistance" without any mention of usage limits?
- afro88 1y ago
  Same. Agents can be very expensive. Plus I have no idea how reliable or effective this actually is in practice. Would love to try it first.
ativzzz 1y ago
This is very cool. I think the primary innovation here is twofold: 1. Remote agent - it's a containerized environment where the agent can run loose and do whatever - it doesn't need approval for user tasks because it's in an isolated environment (though it could still accidentally do destructive actions like edit git history). I think this alone is a separate service that needs to be productionized. When I run claude code in my terminal, automatically spin up the agent in an isolated environment (locally or remotely) and have it go wild. Easy to run things in parallel 2. Deep integration with fly. Everyone will be trying to embed AI deep into their product. Instead of having to talk to chatgpt and copy paste output, I should be able to directly interact with whatever product I'm using and interact with my data in the product using tools. In this case, it's deploying my web app
- deleted 1y ago
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- indigodaddy 1y ago
  look into Kasm workspaces.. great way to spin up remote docker-based linux desktops, and works great as an AI dev environment that you can use wherever you happen to be. There is homedir persistence, and package persistence can be achieved via some extra configuration that allows for Brew homedir-based package persistence. https://hub.docker.com/r/linuxserver/kasm https://hub.docker.com/r/linuxserver/kasm https://www.reddit.com/r/kasmweb/comments/1l7k2o8/workaround_for_package_persistence/ https://www.reddit.com/r/kasmweb/comments/1l7k2o8/workaround...
- risyachka 1y ago
  >> Remote agent - it's a containerized environment where the agent can run loose and do whatever How is this innovation?
  - kasey_junk 1y ago
    Many people have not experienced the async agent workflow yet and fairly the major providers didn’t have offerings for them until a month or two ago. It’s in fact one of my predictors for if they are going to be enthusiastic about agents or not. And you wouldn’t think containerization would be a big leap but this stuff is so new and moving so fast that combining them with existing tech can surprise people.
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krts- 1y ago
This is incredible. It does seem quite expensive compared to Zed or Claude Code now it's on Pro. But neat enough I've burned through the $20 subscription credit despite being a bit of an AI sceptic. This seems to have a much better handle on UI design (unless I'm missing something with the other agents), but as a solo dev I'm becoming quite convinced. It's also got me to try out fly again. I couldn't get Tidewave working but I must try again to see if Tidewave with Claude Code would offer this level of awesome. ps. @fly - please let me buy more credit, I just get an error!
- chrismccord 1y ago
  Thanks for the feedback! Send your fly email to chris@fly.io and I'll get things sorted out. We'll throw you some credits for the trouble :)
  - krts- 1y ago
    Hero.
sergiotapia 1y ago
What model is it using for all the agentic work? What usage limits do we get with the $20 monthly price? Thank you!
unvs 1y ago
Any chance of open sourcing the model instructions for this? Do you feed it all the Phoenix/LiveView/Elixir docs, or have you written more specialised instructions? I find Claude to have quite a bit of problems trying to navigate changesets + forms + streams in my codebase, just wondered if you had any tips of making it understand better :)
qudat 1y ago
Technically this is really. Practically I don’t understand the point. Who is the target demographic? People that don’t have a local dev environment?
- abrookewood 1y ago
  It's not really about the remote IDE. It's about an integrated environment where the agent can do everything it needs (install OS packages, inspect the code, view the app via a browser etc) in order to build what you want. It could end up being the place you 'start' an app, before exporting it and fleshing out the features locally.
  - qudat 1y ago
    So the primary benefit over any other AI agent IDEs is it has access to a browser? Ya I really am not the target demographic for this since I don't use AI agents in my IDE anyway. It does seem to perfectly fit fly.io in the sense that I also don't care about "edge" apps.
losvedir 1y ago
This is very neat, and right up my alley as both someone really into Elixir and who thinks agentic AI is the future. I have a question about how you manage context, and what model you use. Gemini seems the best at working with give context windows right now, but even that has its limitations. Thinking about working with Claude Code, a fair bit of my strategizing is in breaking down work and managing project state to keep context size manageable. I'm watching the linked video and it's amazing seeing it in action, but I'm imagining continuing to work on a project and wondering if it will start losing its way so to speak. Can you have it summarize stuff, and can you start a session clean with those summaries, and have it "forget" files it won't need to use for this next feature, etc?
tough 1y ago
this is the excuse i needed to revisit phoenix-elixir after a decade ty fly team
indigodaddy 1y ago
So is Phoenix.new a Fly.io product, or just under the fly umbrella? Also, is pricing clearly laid out anywhere (including what the additional costs are for permanently deployed/hosted services that arise from Phoenix) ? Didn't dig too hard admittedly, but wasn't obvious where to find or look for pricing information on the front page on mobile
toolhouseAI 1y ago
Hey @chrismccord, very confused but this is a collab between you and the FLY.IO project right? Like I can't eject the app from this and run it myself? This isn't an open source Phoenix project?
- olafura 1y ago
  You can just use git to clone the code
zombiwoof 1y ago
it's wild to me all this progress with AI, but at the same time, on my brand new mac, going through the readme to try out phoenix, it can't even get past the first step without an error (says it can't find postgres), yet the docs say I don't need postgres and it will default to sqllite if postgres and mysql can't be found. hard to put confidence in AI vibe hacks when the basic stuff just doesn't work. * (Mix) The database for Myapp.Repo couldn't be created: killed
psadri 1y ago
I love the idea of Phoenix and server side rendering (I happen to work on SkyMass, a related project). This is a tangential comment and should not detract from what Chris and team have created. I think closing the loop between agent and the running output is a great/critical step forward. However, I find using AI to build transitional Apps with a UI is a bit like improving the way automobile steering wheels are made. In a world that soon won't need steering wheels at all. If the AI is so good to write the code for an App, how much longer before you won't need those Apps in the first place? And then the question is, what will fill the role that Apps play today.
- colecut 1y ago
  I don't think we want to move to a world where everything we use is AI driven all the time. A coded app is significantly more efficient to execute, and more predictable, than dealing with AI in most situations.
  - psadri 1y ago
    I don't disagree that code is far more efficient than inference. But what are those apps? A lot of apps are fetching some data, massaging it, rendering UI to let the user view / update data. Could the AI do some of that "work" for you, so that you don't need those dashboards / buttons / forms in the first place? Maybe you have an agent that does a db query (instead of a human viewing a dashboard) and takes some action (instead of the human clicking a button).
- liampulles 1y ago
  I think it boils down to: if the AI screws up what I asked it to do, who do I have to hold accountable? If the answer is that there is no one I can hold accountable, because the AI agent I used removes any and all onus of responsibility in its terms of service, then I'm not going to use it for anything non-trivial.
travisgriggs 1y ago
I’m torn on “is this the future”. I worked all day on a Phoenix app we’re developing for ag irrigation analysis. Of late, my “let’s see what $20/mo gets you” is Zed with its genetic offerings. It actually writes very little Elixir code for me. Sometimes, I let it have a go, but mostly I end up rewriting that stuff. Elixir is fun, and using the programming model as intended is enlightening. What I do direct it to write a lot is a huge amount of the HEEX stuff for me. With an eventual pass over and clean it up for me. I have not memorized all of the nuances of CSS and html. I do not want to. And writing it has got to be the worst syntactic experience in the history of programming. It’s like someone said people lisp was cool; rather than just gobs of nested parentheses, let’s double, nay triple, no quadruple down on that. We’ll bracket all our statements/elements with a PAIR of hard to type characters, and for funsies, we’ll make them out different words in there. And then when it came to years of how to express lists of things, it’s like someone said “gimme a little bit of ini, case insensitivity, etc”. And every year, we’ll publish new spec of new stuff that preserves the old while adding the new. I digress… I view agentic coding as an indictment on how bad programming has gotten. I’m not saying there wouldn’t be value, but a huge amount of the appeal, is that web tech is like legalese filled with what are probably hidden bugs that are swallowed by browsers in a variety of u predictable ways. What a surprise that we’ve given up and decided the key tools do the probabilistic right thing. It’s not like we had a better chance of being any more correctly precise on our own anyway.
Sytten 1y ago
I am probably doing something wrong but I hate agents for coding. I like the autocomplete and the prompt to generate snippets but when it starts modifying code in many files so fast all at once, tries a bunch of stuff and never know when to stop it pisses me off more than anything else. Because most the time if it had stopped and let me do the 10% last part it would have been actual legit code.
citizenpaul 1y ago
Heyy! Now we know why fly.io was shilling for AI a couple weeks ago. "They are not making money off AI".was the most common response to my pointing out they were shilling AI. Feels good to be right.
- lawn 1y ago
  Maybe you mean the "My AI Skeptic Friends Are All Nuts" blog post on fly.io? Where they have this nugget about plagiarism: > But if you’re a software developer playing this card? Cut me a little slack as I ask you to shove this concern up your ass. No profession has demonstrated more contempt for intellectual property. So I guess if you have concerns about them using any code you upload using this tool you can shove it up your ass.
troad 1y ago
This makes me very uneasy. Not in what it is per se, but in what it shows about the direction of Phoenix. I've been working with Phoenix a lot the last few months, and I like it a lot. But I do get the sense that the project suffers from wanting to perpetually chase the next new thing, even when that comes at the expense of the functional elegance and conceptual cohesiveness that I think is Phoenix' main strength. LiveView is a great example. It's a very neat bit of tech, but it's shoe-horned surprisingly awkwardly into Phoenix. There's now a live view and non-live view way to do almost everything in Phoenix, and each has their own different foibles and edge cases. A lot of code needs to work with both (e.g. auth needs to happen at both levels, basically), meaning a surprising amount of code needs to have two, nearly identical variants: one with traditional Plug idioms, and then another using LiveView equivalents. Quick little view helpers end up with either convoluted 'what mode am I in?' branching, or (more likely) in view-mode-dependent wrappers around view-mode-independent abstractions. This touches even the simplest helpers (what is the current path?) and becomes more cumbersome from there. (And given the lack of static analysis for views, it can be non-trivial to even find out what is and isn't actually working where.) Not every website should be a live view (e.g. hiking directions, for example), but that is clearly the direction of travel in Phoenix. Non-live views get the disparaging moniker 'dead views', and the old Phoenix.HTML helpers have been depreciated in favour of <.form />-style live components. The generators depend on those, plus Tailwind, Hero Icons and (soon) DaisyUI, all fetched live from various places on the Internet on build. This tight coupling to trendy dependencies will age poorly, and it makes for bumpy on-boarding (opinionated and tightly coupled isn't necessarily a smoother experience, just a more inflexible one). So with all of that in mind, while I'm not shocked to see Phoenix jump on the vibe coding hype train, I guess I am disappointed. The revelation that AI is now writing PRs for Phoenix itself is not confidence inspiring. I rely on frameworks like Phoenix because I don't want to have to think about the core abstractions around getting a website to my users; I want to focus on my business logic. But implicit in that choice is the assumption that someone is thinking about those things. If it's AI pushing out Phoenix updates now, my trust level and willingness to rely on this code drops dramatically. I also do not expect Phoenix' fraying conceptual cohesiveness to get any better if that's the way we're headed. Phoenix is still an amazing piece of tech, but I wish I felt more at ease about its future trajectory.
itsautomatisch 1y ago
Burnt through some credits pretty quickly. The first few minutes of using it felt like a glimpse of what it was supposed to be like, but otherwise it spent a lot of time not getting basic things right with the UI and before I knew it I was done. Roughly 90 minutes for $20 it's not a good value when you can ostensibly have the same experience on your computer and have control over every aspect. I still can't clone the latest revised version of the codebase it created to my local computer. Between that and Fly's non-existent documentation, no usage meter of some kind, and the lack of unpaid support (even though I am paying to use the service?) makes me want to avoid Fly, which is unfortunate because I think it does a lot of things right, especially the tunneling and dev experience outside of phoenix.new.
ferfumarma 1y ago
I love everything I read about Phoenix. It's definitely the framework I'm going to use the next time I need to scratch an itch. Having a full stack that is easy to use as a learning sandbox is incredibly helpful in that regard, so this looks amazing.
liampulles 1y ago
This is very cool! I will say though, my spidey senses kick in when looking at stuff like this, and make me wonder about how much I'm going to get vendored in here. Could I use it develop a site off fly.io? If the answer is no, then I'd say this is cool and I think useful for people who need something quick and simple and out of the box, but not something I would ever use on a serious production project.
- andy_ppp 1y ago
  It’s just producing Elixir/Phoenix code that is stored in GitHub and can be deployed anywhere.
- loloquwowndueo 1y ago
  The answer is yes. What would you say then? There’s a “clone Git repo” thing in the left side bar, use that to clone the project locally, mix deps.get, mix phx.serve and you’re up. You can deploy this anywhere you want.
  - liampulles 1y ago
    If the DB, Auth libraries and such are not tied to fly.io, then yep that's cool. Happy
kuon 1y ago
I really wish I could move to those nice new editors, but as a vim user I just feel paralyzed when I cannot use vim bindings. And all "emulations" I tried are just incomplete.
- timeinput 1y ago
  I'm with you. I'm going to try Zed in the next couple days based on the response to my comment here. https://news.ycombinator.com/item?id=44322560 https://news.ycombinator.com/item?id=44322560 . I'm stuck with vim. My fingers nearly only work vim, but I managed to move to neovim, which worked. Maybe (something else) can work too.
- loloquwowndueo 1y ago
  You can pull the repo, tweak it locally with Vim, push it back and ask the LLM to work on top of that. No need to use the built in IDE if you don’t like it.
- chrismccord 1y ago
  as an avid vim user who moved to emacs evil-mode for a better vim than vim, and now who uses vscode with vscode-vim, it pains me to admit a web browser based editor is a better vim than vim. Somehow starts faster and is less kludgey and more scriptable. You can install extensions on phoenix.new, so vim is not a blocker for you. I drive vim emulation in it every day both on desktop app and within phoenix.new. Couldn't use it without it :)
  - kuon 1y ago
    My main issue with vim emulation is that you cannot do file management and windows management. In my vim workflow I keep splitting/unsplitting windows and I like to have a file browser I can navigate with vim bindings.
tobyhinloopen 1y ago
My primary concern with Phoenix is how bad it performs in LLMs and I basically went back to Node/React/Rails for LLMs. This is very exciting and I’ll check it out!
- josefrichter 1y ago
  What you mean by performs bad in LLMs?
  - tobyhinloopen 1y ago
    LLMs don’t know Elixir/Phoenix very well
    - josefrichter 1y ago
      Claude Code is pretty proficient in it. Others, not so much. True.
      - tobyhinloopen 1y ago
        Did you consider creating a LLM.txt and some variants for Phoenix? Some libraries have text-based documentation for LLMs which works great in my experience.
artur_makly 1y ago
For us SaaS Founders, GrowthHackers, Product folks, us non-devs.. What are some solid use-cases for it today?
colecut 1y ago
I am a long time php dev who has been interested in learning elixir/phoenix for a while but never quite motivated enough. I saw this and thought, if this doesn't get me to give it a go, nothing will. Less than 45 minutes after signing up for fly.io, I have a multi-room tic tac toe game deployed. https://tic-tac-toe-cyber.fly.dev/ https://tic-tac-toe-cyber.fly.dev/ I had it build the game, opting for a single room at first to see if that worked. Then I had it add multiple rooms on a different git branch in case that didn't work. It worked great. I learned very little about elixir, phoenix, or deploying to fly.io up to this point, and I already have a nice looking app deployed and running. I know a lot of devs will hate that this is possible, and it is up to me now to look at the steps it took to create this and really understand what is happening, which are broken down extremely simply for me... I will do this because I want to learn. I bet a lot of people won't bother to do that. But those people never would have had apps in the first place and now they can. If they are creating fun experiences and not banking apps, I think that is still great. You guys have been releasing amazing things for years only to be poorly replicated in other languages years later.. but you really outdid yourselves here. I'm blown away. edit: is there a way to see how much of my credits were used by building this?
- jonahx 1y ago
  Was the graphic design created from prompts too? It's surprisingly nice, especially considering you spent 45 minutes on it.
  - colecut 1y ago
    I told it that I wanted a two player tic tac toe game. it give me a selection of "styles" and I chose neon retro.. I probably could have been more creative and typed in my own suggestion. Other than that, I said absolutely nothing about how I wanted the layout. It came up with the idea of listing all active games on the homepage, with the number of players in each, all on its own. I went from "I want a two player tic tac toe game" to having one, and then added multiple rooms, and deployed it all in under 45 minutes, with little input other than that..
- chrismccord 1y ago
asmodeuslucifer 1y ago
Well of course I have to test it. Disabled on news.ycombinator.com
poisonta 1y ago
Phoenix needs an ActiveRecord-like database abstraction layer. Many Rails developers try Phoenix at some point because they may need better performance. They’re so accustomed to the Rails structure that they assume Rails has done everything right. However, Ecto and ActiveRecord are two very different beasts. When Rails developers try out Ecto, they often feel there’s too much boilerplate and believe the Rails design is much more intuitive. This, I think, is one reason Phoenix struggles to attract Rails developers. If it can’t please Rails users, it will rarely appeal to others.
- lawn 1y ago
  The Ash framework is a data abstraction layer you light want to check out, although I'm not familiar with Rails/ActiveRecord to tell if it's closer to what they're after.
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mcdirty 1y ago
Is the site down?
artirdx 1y ago
Mindblowing! This is 100x VB6. The generated UIs are beautiful and professional. I am still trying it out and building an app for tracking expenses but it is working very well. The conversational dialogue it has with the developer is just fantastic. I am amazed at how clear the user experience was in Chris' mind. I am not sure what LLM is being used but this is better experience than any LLM. Given this is first version, I look forward to what comes next! Few issues: 1. The 150 message limit is understable but it suddenly pops up and you lose significant work. I was working on UI mockup and just as I had finished and was ready to go on implementation, this limit appeared and significant part of my work was lost. 2. After the first credit, the credit seems to exhaust pretty fast which makes it expensive, especially when you are trying it out. 3. Also I don't understand when you ask it to prototype different screens, why does it overwrites the same file. 4. It is not able to stop to seek user feedback but keeps trying different approach which kind of exhausts the credit. It would be nice if it describes its approach, so the human developer can provide their feedback. 5. It seems it is using OpenAI because it is often self-congratulatory to the point of being annoying sometimes.
aytigra 1y ago
A bit sad that the language and framework so enjoyable to write an read will be mostly hidden in a coding box. And thinking about it made me realize that soon there will be a completely different programming language used solely by coding agents. ChatGPT gives an interesting take on this, "The fundamental shift is that such a language wouldn’t be written or read, but reasoned about and generated. It would be more like an interlingua between symbolic goals and executable semantics, verbose, unambiguous, self-modifying, auto-verifiable, evolving alongside the agents that use it").

639 points by wut42 1y ago

Ah man I'm really happy to see this and excited to try it out. As an Elixir enthusiast I've been worried that Elixir would fall behind because the LLMs don't write it as well as they write bigger languages like Python/JS. So I'm really glad to see such active effort to rectify this problem. We're in safe hands.

zorrolisto 1y ago
Same, I watched a video from Theo where he says Next.js and Python will be the best languages because LLMs know them well, but if the model can infer, it shouldn’t be a problem.
- rramon 1y ago
  Folks on YouTube have used Claude Code and the new Tidewave.ai MCP (for Elixir and Rails) to vibe code a live polling app in Cursor without writing a line of code. The 2hr session is on YT.
  - rahimnathwani 1y ago
    This one? https://www.youtube.com/live/V2b6QCPgFTk https://www.youtube.com/live/V2b6QCPgFTk
    - rramon 1y ago
      That's the one.
- dingnuts 1y ago
  since models can't reason, as you just pointed out, and need examples to do anything, and the LLM companies are abusing everyone's websites with crawlers, why aren't we generating plausible looking but non working code for the crawlers to gobble, in order to poison them? I mean seriously, fuck everything about how the data is gathered for these things, and everything that your comment implies about them. The models cannot infer. The upside of my salty attitude is that hordes of vibe coders are actively doing what I just suggested -- unknowingly.
  - fragmede 1y ago
    But the models can run tools, so wouldn't they just run the code, not get the expected output, and then exclude the bad code from their training data?
    - bee_rider 1y ago
      That seems like a feedback loop that’s unlikely to exist currently. I guess if intentionally plausible but bad data became a really serious problem, the loop could be created… maybe? Although it would be necessary to attribute a bit of code output back to the training data that lead to it.
  - Imustaskforhelp 1y ago
    For what its worth, AI already has subpar data. Atleast this is what I've heard. I am not sure, but the cat is out of the box. I don't think we can do anything at this point.
- sieabahlpark 1y ago
  [dead]
acedTrex 1y ago
LLMs not writing it well might be the biggest current selling point of elixir lol.
- zupa-hu 1y ago
  Oh lol I love that angle!
- mattbrewsbytes 1y ago
  Selling point from a developer and career perspective for sure. Its also fun to program in and at least for me made me think about solutions differently. Its a negative point for engineering leaders that are the decision makers on tech stacks as it relates to staffing needs. LLMs not writing it well, developers that know it typically needing higher compensation, a DIY approach to libraries when there aren't any or they were abandoned and haven't kept pace with deprecations/changes, etc. In the problem space of needing a web framework to build a SaaS, to an engineering leader there are a lot of other better choices on tech stack that work organizationally better (i.e. not comparing tech itself or benchmarks, comparing staffing, ecosystem, etc.) to solve web SaaS business problems. I don't know where I stand personally since I'm not at the decision maker level, just thought I'd point out the non-programmer thought process I've heard.
throwawaymaths 1y ago
in principle llms should do better on immutable languages since there is no risk a term will get modified by a distant function call.
- bevr1337 1y ago
  In my experience, it's the functional part, not immutability, where they fall short. Any LLM can write immutable C# because it's easy and there's incredible amounts of training data.
  - throwawaymaths 1y ago
    good news, "immutable" is pretty much the only way that elixir is "functional" except for lambdas being first class datatypes (which is almost every language now)
mrcwinn 1y ago
Worried it might fall behind… further? I love LiveView, Phoenix, Elixir, OTP. But the ecosystem is a wasteland of abandoned packages. If Phoenix.new helps solve that problem, I’m all for the effort. But otherwise, the sole focus of the community leaders of Elixir should be squarely and exactly focused on creating the incentives and dynamics to grow the base. Compare, for example, Mastra in TypeScript or PydanticAI in Python. Elixir? Nothing. Not here to bash. It’s more just a disappointment because otherwise I think nothing comes close.
- uncircle 1y ago
  All languages are a wasteland of abandoned packages, i.e. there is a very long tail of stuff no one has maintained for years. It’s all relative to the mindshare. For its size, Elixir is doing quite well.
  - erichocean 1y ago
    Most languages require maintenance. Some languages—Clojure is a good example—have packages from 10 years ago, entirely unmaintained, that still work great because no maintenance is needed.
    - arrowsmith 1y ago
      This is also true for Elixir though. A lot of "unmaintained" Elixir packages still work fine.
      - sodapopcan 1y ago
        That's their point (I think, lol).
    - spiderice 1y ago
      In my experience, Elixir is very much on that end of the spectrum as well. I'm wondering if GGP just considers packages that don't have updates for 6 months as "unmaintained" or "dead" because they come from Javascript world where everything is, well... you know.
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bad_haircut72 1y ago
This is such a weird meme, Claude crushes elixir especially a fullstack app in liveview
- heeton 1y ago
  Yea CC is great with phoenix / liveview. It’s been doing things that teach me new tricks about elixir I didn’t know yet.
  - ferfumarma 1y ago
    What's a good place to start for a completely naive but interested user?
    - heeton 1y ago
      Sorry, I only just saw this comment. Feel free to reach out (email in profile) and I’d be happy to chat.
te_chris 1y ago
Claude and o3 are both excellent (if a bit erratic) elixir developers.
pawelduda 1y ago
Claude 3.5 produces very good Elixir/Phoenix code. Haven't tried 3.7 much but I assume it's only going to get better from here
neya 1y ago
I use o3, it's really good with Elixir. I prefer it to Claude, but Claude does a decent job as well. If you want to take your website and business down, use ChatGPT-4o's code
bluehatbrit 1y ago
This last few weeks I've been going hard on LLMs to put together a new prototype project. I've exclusively been using Claude Sonnet 3.7 within Zed (via github copilot) and it' fantastic. From time to time it tries to do something a little old-school, but nothing significant really. It's very capable at spitting out entire new features, even in liveview. Over all the experience has very productive, and at least on-par with my recent work on similar sized python and nextjs applications. I think because I'm using mostly common and well understood packages it has a big leg up. I also made sure to initialise the phoenix project myself to start with so it didn't try to go off on some weird direction.
- indigodaddy 1y ago
  Assuming you are on the $20 Zed plan? Has the 500 prompts/mo been sufficient for you? I'm debating between the Zed and Claude $20 plans-- no doubt I'd get better value from Zed's?
  - bluehatbrit 1y ago
    I'm on the free plan and have been using it via GitHub copilot instead, as the current project is a work one and they pay for that. Before this I did a small project and I hit the 50 free tier limit through Zed by the time I was about 90% done. It was a small file drop app where internal users could create upload links, share them with people who could use them to upload a file. The internal user could then download that file. So it was very basic, but it churned out a reasonable UI and all the S3 compatible integration, etc. I had to intervene a bit and obviously was reviewing everything and tweaking where needed. But I was surprised at how far I got on the 50 free prompts. It's hard to know what you really get for that prompt limit though as I probably had a much higher number of actual prompts than they were registering. It's obviously using some token calculation under the hood and it's not clear what that is. All in all I probably had about 60-70 actual prompts I ran through it. My gut says 500/mo would feel limited if I was going full "vibe" and having the LLM do basically everything for me every day. That said, this is the first LLM product I'm considering personally paying for. The integration with Zed is what wins for me over Claude, where you'd have to pay for API credits or use Claude Code. The way they highlight code changes and stuff really is nice. Bit of a brain dump, sorry about that!
nxobject 1y ago
Yeah – as someone who works in Common Lisp, I wish there was way to do complementary training for LLMs with existing corpora of codebases. Being able to read access documentation doesn't do much, unfortunately, to help with more general issues with correctness of output.
victorbjorklund 1y ago
I found them to be pretty solid for writing Elixir (not perfect but neither is it with JS) the last couple of months.

ipnon 1y ago

Chris is a hacker’s hacker.

nixpulvis 1y ago
A hacker's hacker who charges for closed source AI tools which work in hosted environments only. Yea, right.
- abrookewood 1y ago
  Come on, devs need to eat. Companies need cash to employ people. After all that he has done for open source, you're complaining that something isn't free? You know you can export the code at any time right?
  - nixpulvis 1y ago
    I'm not saying he's a bad dev, just hardly fits the hacker ethos. We want things we can tinker and toy with from the inside.

martypitt 1y ago

This is really cool! And, that you did it in a few weeks is insane. How did you get VS Code embedded in your app? I'm aware of projects like Monaco, and that vscode.dev exists - so it's clearly possible - but I didn't realize it was something others could build upon? Again, kudos!

moffers 1y ago

The mental models of Elixir/OTP and AI Agents are very compatible. I’ve felt for a long time that it would be one of the best platforms for building AI agents.

zupa-hu 1y ago
Would you elaborate why?

rramon 1y ago

Very cool. Does it use Phoenix 7 or 8 in the video?

arrowsmith 1y ago
1.7 or 1.8, not 7 or 8
- rramon 1y ago
  Thanks for correcting my typo.
chrismccord 1y ago
1.8rc, which is going 1.8.0 momentarily

themgt 1y ago

This looks really cool, but I gotta say I'm a bit uneasy with the apparent(?) closed-source + hosted + branding. "mix phx.new" is the way to generate a new Phoenix project, but "Phoenix.new" is closed source Fly.io product for building Phoenix projects? Feels like we're getting into a weird situation if LLM providers are publishing open source agentic coding tools and OSS web app frameworks are publishing closed source/non-BYOK agentic coding tool. I realize this may not be an official "Phoenix" project but it seems analogous to DHH releasing a closed-source/hosted "Rails.new" service.

pier25 1y ago

I'm surprised they are investing into this. I checked Phoenix recently because I was interested in LiveView and there isn't even an official AWS SDK for Elixir. Honestly doubt the AI stuff is going to move the needle much if you can't even have a dependable S3 client.

conradfr 1y ago
But there's two actively non-official maintained libs.
olafura 1y ago
What are you talking about, there has been a AWS client forever and I've never had a problem. It's not something you really need an official sdk for they are anyway often just reference because you might want different performance characteristics. https://hex.pm/packages/ex_aws https://hex.pm/packages/ex_aws https://hex.pm/packages/ex_aws_s3 https://hex.pm/packages/ex_aws_s3 I've usually not seen more than 3 or so official SDK for most services and there are a lot more programming languages than that. For example Microsoft's Graph API doesn't have an official Ruby client, they have one that sort of works.
- Snakes3727 1y ago
  Neither of them are official which is often a non starter for some large enterprise customers.
  - pier25 1y ago
    Not only large enterprise customers. Anyone who's thinking mid or long term.
    - sysashi 1y ago
      Why do you need an official SDK to make http calls?
      - 1y ago

chrismccord 1y ago

Phoenix creator here. I'm happy to answer any questions about this! Also worth noting that phoenix.new is a global Elixir cluster that spans the planet. If you sign up in Australia, you get an IDE and agent placed in Sydney.

troupo 1y ago
I know it's early days, but here's a must-have wish list for me: - ability to run locally somehow. I have my own IDE, tools etc. Browser IDEs are definitely not something I use willingly. - ability to get all code, and deploy it myself, anywhere --- Edit: forgot to add. I like that every video in Elixir/Phoenix space is the spiritual successor to "15-minute rails blog" from 20 year ago. No marketing bullshit, just people actually using the stuff they build.
- chrismccord 1y ago
  You can push and pull code to and from local desktop already: hamburger menu => copy git clone/copy git push. You could also have it use GitHub and do PRs for a codex/devin style workflows. Running phoenix.new itself locally isn't something we're planning, but opening the runtime for SSH access is high on our list. Then you could do remote ssh access with local vscode or whatever.
  - prophesi 1y ago
    > Running phoenix.new itself locally isn't something we're planning So no plans to open the source code?
    - chrismccord 1y ago
      confirm
    - abrookewood 1y ago
      Everyone has to eat.

nilirl 1y ago

Beautiful demo! How do I build agents like this? Does anyone know any great resources to learn how to design agents? Tool agnostic resources would be awesome.

chrismccord 1y ago
Thanks! Everything is overly complicated in this space. It's probably far easier than you think. The open secret is it's just a loop that POST [provider]/chat/completions. Elixir is particularly well suited here. In Elixir this is a genserver doing http posts and reacting to the token stream. The LiveView chat gets messages from the genserver agent regardless of where it is on the planet, and the agent also communicates with the phoenix channel websocket talking to the IDE machines with regular messages, again anywhere they are on the planet. I talk about this quite a bit in my ElixirConfEU talk and distill things down: https://youtu.be/ojL_VHc4gLk?si=MzQmz-vofWxWDrmo&t=1040 https://youtu.be/ojL_VHc4gLk?si=MzQmz-vofWxWDrmo&t=1040
- nilirl 1y ago
  Wow, thank you for the link, it clarified how tool calling and "choice-making" works. It's like helping LLMs use a computer; like building an interface for it. Ok, this is enough to get me started.

CollinEMac 1y ago

I'm a little surprised by the sentiment here that LLMs don't do well with Elixir. I've had a pretty good experience using AI tools on Phoenix/Elixir side projects.

arrowsmith 1y ago
LLMs are definitely a lot better at Elixir than they used to be - the gap has closed somewhat. I still perceive a gap though, especially when trying to do more complicated things in Phoenix and LiveView (as opposed to just raw Elixir.) Which LLMs do you use that you find are best with Elixir/Phoenix?
- CollinEMac 1y ago
  I haven't really used much other than Claude. I guess I should also note that I haven't really used LiveView much.
vaer-k 1y ago
I've only used LLMs with Elixir, so I don't have any other experience for comparison, but I've found that although Claude frequently employs the wrong approaches in Elixir, I usually know when he'll have trouble and just ask him to read pertinent documentation first. So long as he's read the manual he seems to do just fine.

krainboltgreene 1y ago

I've wasted a lot of time and energy on stuff that doesn't matter, so I can hardly judge anyone else on what they focus on, but man does it feel bad to have community leaders actively focus on building out tooling that is anti-worker. I think the only way I'd feel more conflicted is if Fly.io started building weapons systems for the military. I guess that wouldn't be shocking considering some of their lead's beliefs.

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mrkurt 1y ago
It's safe to say that if either Chris or I believed this to be anti worker, we wouldn't be working on it. He's spent the last 10+ years working on Phoenix specifically to improve the lives of the people doing the work. My experience with software development is maybe different than yours. There's a massive amount of not-yet-built software that can improve peoples' lives, even in teeny tiny ways. Like 99.999% of what should exist, doesn't. Building things faster with LLMs makes me more capable. It (so far) has not taken work away from the people I work with. It has made them more capable. We can all build better tools, and faster than we did 12 months ago. Automation is disruptive to peoples' lives. I get that. It decreases the value of some hard earned skills. Developer automation, in my life at least, has also increased the value of other peoples' skills. I don't believe it's anti worker to build more tools for builders.
- jonator 1y ago
  Exactly. And as more software is written, the demand and possible set of softwares increase. It's really a matter of positive sum/growth mindset vs scarcity/status quo mindset.
  - hooverd 1y ago
    Maybe, but it's zero sum to the people with money. We saw wage growth in the lowest end during the Biden admin and it drove the bosses insane.

__0x01 1y ago

What LLM does Phoenix.new use?

chrismccord 1y ago
claude 4 sonnet as the main driver atm, and a mix of smaller models depending on the scenario
- tptacek 1y ago
  I'm building an agent right now (or rather, extending an agent I build a few weeks ago in a couple hours) and I would love to hear more about which scenarios get assigned to which models. (I almost just asked you on company Slack but figured the answer would be more broadly interesting.)
ethan_smith 1y ago
Based on the blog post, Phoenix.new uses Claude 3 Opus as its underlying model, which explains its strong performance with Elixir/Phoenix codebases.

rustc 1y ago

"Sign in with fly.io" takes me to a page asking me to pay $20 but the plan details are vague - what exactly is included in "$20/mo of Built-In AI Assistance Builds, refactors, and debugs right in your IDE"?

tptacek 1y ago
This is a situation where we've been pushing on Chris to get this out into the world quickly, and there's a lot of packaging stuff like this that isn't fully put together yet. Thanks for calling it out! We'll get to it over the next week.

mcdirty 1y ago

This is great. I had to back out of a phoenix project and rewrite it in Django because I couldn't get good AI assistance. I'm pretty inexperienced with Elixir and Phoenix but understand the benefits enough to want to make projects in it. So this is really cool.

causal 1y ago
I had this experience too. Though most of my issues were with my model not necessarily with Elixir itself so much as understanding the Phoenix model, state, and CLI. Maybe even differences in versions? Wasn't always clear.
dontlaugh 1y ago
I find that baffling. Why not just write the Elixir yourself?
- prophesi 1y ago
  Not just baffling, but concerning. LLM's are great for learning new languages, but terrible for outputting code you don't understand yet hope to maintain.
  - abrookewood 1y ago
    Yet, more and more people are going to be doing exactly this.

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sockboy 1y ago

Integrating AI assistance directly into an Elixir IDE could boost productivity, especially for newcomers. Excited to see how remote SSH and local workflows develop!

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gavmor 1y ago

Phoenix.new looks powerful, and I'll definitely play with it. I've been daydreaming of an agentic framework that maximally exploits BEAM. This isn't that, but maybe jido[0] is what I'm looking for. 0. https://github.com/agentjido/jido https://github.com/agentjido/jido

fridder 1y ago
TIL; That is a very interesting library
- mstibbard 1y ago
  This thread on Elixir Forum is a good read if you are considering building agents with Elixir. Jido's author weighs in also. https://elixirforum.com/t/is-anyone-working-on-ai-agents-in-elixir/69989/1 https://elixirforum.com/t/is-anyone-working-on-ai-agents-in-...

johnwheeler 1y ago

Why wouldn't LLMs work as well with Elixir as python or JS? LLMs don't parse an AST.

lawn 1y ago
Because of the amount of Python and JS in the wild is much more than the amount of Elixir code, so the LLMs have much more data to base their answers on.
- johnwheeler 1y ago
  Thanks

jsmo 1y ago

Hmm, just signed up to check it out but no trial just "$20/mo of Built-In AI Assistance" without any mention of usage limits?

afro88 1y ago
Same. Agents can be very expensive. Plus I have no idea how reliable or effective this actually is in practice. Would love to try it first.

ativzzz 1y ago

This is very cool. I think the primary innovation here is twofold: 1. Remote agent - it's a containerized environment where the agent can run loose and do whatever - it doesn't need approval for user tasks because it's in an isolated environment (though it could still accidentally do destructive actions like edit git history). I think this alone is a separate service that needs to be productionized. When I run claude code in my terminal, automatically spin up the agent in an isolated environment (locally or remotely) and have it go wild. Easy to run things in parallel 2. Deep integration with fly. Everyone will be trying to embed AI deep into their product. Instead of having to talk to chatgpt and copy paste output, I should be able to directly interact with whatever product I'm using and interact with my data in the product using tools. In this case, it's deploying my web app

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indigodaddy 1y ago
look into Kasm workspaces.. great way to spin up remote docker-based linux desktops, and works great as an AI dev environment that you can use wherever you happen to be. There is homedir persistence, and package persistence can be achieved via some extra configuration that allows for Brew homedir-based package persistence. https://hub.docker.com/r/linuxserver/kasm https://hub.docker.com/r/linuxserver/kasm https://www.reddit.com/r/kasmweb/comments/1l7k2o8/workaround_for_package_persistence/ https://www.reddit.com/r/kasmweb/comments/1l7k2o8/workaround...
risyachka 1y ago
>> Remote agent - it's a containerized environment where the agent can run loose and do whatever How is this innovation?
- kasey_junk 1y ago
  Many people have not experienced the async agent workflow yet and fairly the major providers didn’t have offerings for them until a month or two ago. It’s in fact one of my predictors for if they are going to be enthusiastic about agents or not. And you wouldn’t think containerization would be a big leap but this stuff is so new and moving so fast that combining them with existing tech can surprise people.

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krts- 1y ago

This is incredible. It does seem quite expensive compared to Zed or Claude Code now it's on Pro. But neat enough I've burned through the $20 subscription credit despite being a bit of an AI sceptic. This seems to have a much better handle on UI design (unless I'm missing something with the other agents), but as a solo dev I'm becoming quite convinced. It's also got me to try out fly again. I couldn't get Tidewave working but I must try again to see if Tidewave with Claude Code would offer this level of awesome. ps. @fly - please let me buy more credit, I just get an error!

chrismccord 1y ago
Thanks for the feedback! Send your fly email to chris@fly.io and I'll get things sorted out. We'll throw you some credits for the trouble :)
- krts- 1y ago
  Hero.

sergiotapia 1y ago

What model is it using for all the agentic work? What usage limits do we get with the $20 monthly price? Thank you!

unvs 1y ago

Any chance of open sourcing the model instructions for this? Do you feed it all the Phoenix/LiveView/Elixir docs, or have you written more specialised instructions? I find Claude to have quite a bit of problems trying to navigate changesets + forms + streams in my codebase, just wondered if you had any tips of making it understand better :)

qudat 1y ago

Technically this is really. Practically I don’t understand the point. Who is the target demographic? People that don’t have a local dev environment?

abrookewood 1y ago
It's not really about the remote IDE. It's about an integrated environment where the agent can do everything it needs (install OS packages, inspect the code, view the app via a browser etc) in order to build what you want. It could end up being the place you 'start' an app, before exporting it and fleshing out the features locally.
- qudat 1y ago
  So the primary benefit over any other AI agent IDEs is it has access to a browser? Ya I really am not the target demographic for this since I don't use AI agents in my IDE anyway. It does seem to perfectly fit fly.io in the sense that I also don't care about "edge" apps.

losvedir 1y ago

This is very neat, and right up my alley as both someone really into Elixir and who thinks agentic AI is the future. I have a question about how you manage context, and what model you use. Gemini seems the best at working with give context windows right now, but even that has its limitations. Thinking about working with Claude Code, a fair bit of my strategizing is in breaking down work and managing project state to keep context size manageable. I'm watching the linked video and it's amazing seeing it in action, but I'm imagining continuing to work on a project and wondering if it will start losing its way so to speak. Can you have it summarize stuff, and can you start a session clean with those summaries, and have it "forget" files it won't need to use for this next feature, etc?

tough 1y ago

this is the excuse i needed to revisit phoenix-elixir after a decade ty fly team

indigodaddy 1y ago

So is Phoenix.new a Fly.io product, or just under the fly umbrella? Also, is pricing clearly laid out anywhere (including what the additional costs are for permanently deployed/hosted services that arise from Phoenix) ? Didn't dig too hard admittedly, but wasn't obvious where to find or look for pricing information on the front page on mobile

toolhouseAI 1y ago

Hey @chrismccord, very confused but this is a collab between you and the FLY.IO project right? Like I can't eject the app from this and run it myself? This isn't an open source Phoenix project?

olafura 1y ago
You can just use git to clone the code

zombiwoof 1y ago

it's wild to me all this progress with AI, but at the same time, on my brand new mac, going through the readme to try out phoenix, it can't even get past the first step without an error (says it can't find postgres), yet the docs say I don't need postgres and it will default to sqllite if postgres and mysql can't be found. hard to put confidence in AI vibe hacks when the basic stuff just doesn't work. * (Mix) The database for Myapp.Repo couldn't be created: killed

psadri 1y ago

I love the idea of Phoenix and server side rendering (I happen to work on SkyMass, a related project). This is a tangential comment and should not detract from what Chris and team have created. I think closing the loop between agent and the running output is a great/critical step forward. However, I find using AI to build transitional Apps with a UI is a bit like improving the way automobile steering wheels are made. In a world that soon won't need steering wheels at all. If the AI is so good to write the code for an App, how much longer before you won't need those Apps in the first place? And then the question is, what will fill the role that Apps play today.

colecut 1y ago
I don't think we want to move to a world where everything we use is AI driven all the time. A coded app is significantly more efficient to execute, and more predictable, than dealing with AI in most situations.
- psadri 1y ago
  I don't disagree that code is far more efficient than inference. But what are those apps? A lot of apps are fetching some data, massaging it, rendering UI to let the user view / update data. Could the AI do some of that "work" for you, so that you don't need those dashboards / buttons / forms in the first place? Maybe you have an agent that does a db query (instead of a human viewing a dashboard) and takes some action (instead of the human clicking a button).
liampulles 1y ago
I think it boils down to: if the AI screws up what I asked it to do, who do I have to hold accountable? If the answer is that there is no one I can hold accountable, because the AI agent I used removes any and all onus of responsibility in its terms of service, then I'm not going to use it for anything non-trivial.

travisgriggs 1y ago

I’m torn on “is this the future”. I worked all day on a Phoenix app we’re developing for ag irrigation analysis. Of late, my “let’s see what $20/mo gets you” is Zed with its genetic offerings. It actually writes very little Elixir code for me. Sometimes, I let it have a go, but mostly I end up rewriting that stuff. Elixir is fun, and using the programming model as intended is enlightening. What I do direct it to write a lot is a huge amount of the HEEX stuff for me. With an eventual pass over and clean it up for me. I have not memorized all of the nuances of CSS and html. I do not want to. And writing it has got to be the worst syntactic experience in the history of programming. It’s like someone said people lisp was cool; rather than just gobs of nested parentheses, let’s double, nay triple, no quadruple down on that. We’ll bracket all our statements/elements with a PAIR of hard to type characters, and for funsies, we’ll make them out different words in there. And then when it came to years of how to express lists of things, it’s like someone said “gimme a little bit of ini, case insensitivity, etc”. And every year, we’ll publish new spec of new stuff that preserves the old while adding the new. I digress… I view agentic coding as an indictment on how bad programming has gotten. I’m not saying there wouldn’t be value, but a huge amount of the appeal, is that web tech is like legalese filled with what are probably hidden bugs that are swallowed by browsers in a variety of u predictable ways. What a surprise that we’ve given up and decided the key tools do the probabilistic right thing. It’s not like we had a better chance of being any more correctly precise on our own anyway.

Sytten 1y ago

I am probably doing something wrong but I hate agents for coding. I like the autocomplete and the prompt to generate snippets but when it starts modifying code in many files so fast all at once, tries a bunch of stuff and never know when to stop it pisses me off more than anything else. Because most the time if it had stopped and let me do the 10% last part it would have been actual legit code.

citizenpaul 1y ago

Heyy! Now we know why fly.io was shilling for AI a couple weeks ago. "They are not making money off AI".was the most common response to my pointing out they were shilling AI. Feels good to be right.

lawn 1y ago
Maybe you mean the "My AI Skeptic Friends Are All Nuts" blog post on fly.io? Where they have this nugget about plagiarism: > But if you’re a software developer playing this card? Cut me a little slack as I ask you to shove this concern up your ass. No profession has demonstrated more contempt for intellectual property. So I guess if you have concerns about them using any code you upload using this tool you can shove it up your ass.

troad 1y ago

This makes me very uneasy. Not in what it is per se, but in what it shows about the direction of Phoenix. I've been working with Phoenix a lot the last few months, and I like it a lot. But I do get the sense that the project suffers from wanting to perpetually chase the next new thing, even when that comes at the expense of the functional elegance and conceptual cohesiveness that I think is Phoenix' main strength. LiveView is a great example. It's a very neat bit of tech, but it's shoe-horned surprisingly awkwardly into Phoenix. There's now a live view and non-live view way to do almost everything in Phoenix, and each has their own different foibles and edge cases. A lot of code needs to work with both (e.g. auth needs to happen at both levels, basically), meaning a surprising amount of code needs to have two, nearly identical variants: one with traditional Plug idioms, and then another using LiveView equivalents. Quick little view helpers end up with either convoluted 'what mode am I in?' branching, or (more likely) in view-mode-dependent wrappers around view-mode-independent abstractions. This touches even the simplest helpers (what is the current path?) and becomes more cumbersome from there. (And given the lack of static analysis for views, it can be non-trivial to even find out what is and isn't actually working where.) Not every website should be a live view (e.g. hiking directions, for example), but that is clearly the direction of travel in Phoenix. Non-live views get the disparaging moniker 'dead views', and the old Phoenix.HTML helpers have been depreciated in favour of <.form />-style live components. The generators depend on those, plus Tailwind, Hero Icons and (soon) DaisyUI, all fetched live from various places on the Internet on build. This tight coupling to trendy dependencies will age poorly, and it makes for bumpy on-boarding (opinionated and tightly coupled isn't necessarily a smoother experience, just a more inflexible one). So with all of that in mind, while I'm not shocked to see Phoenix jump on the vibe coding hype train, I guess I am disappointed. The revelation that AI is now writing PRs for Phoenix itself is not confidence inspiring. I rely on frameworks like Phoenix because I don't want to have to think about the core abstractions around getting a website to my users; I want to focus on my business logic. But implicit in that choice is the assumption that someone is thinking about those things. If it's AI pushing out Phoenix updates now, my trust level and willingness to rely on this code drops dramatically. I also do not expect Phoenix' fraying conceptual cohesiveness to get any better if that's the way we're headed. Phoenix is still an amazing piece of tech, but I wish I felt more at ease about its future trajectory.

itsautomatisch 1y ago

Burnt through some credits pretty quickly. The first few minutes of using it felt like a glimpse of what it was supposed to be like, but otherwise it spent a lot of time not getting basic things right with the UI and before I knew it I was done. Roughly 90 minutes for $20 it's not a good value when you can ostensibly have the same experience on your computer and have control over every aspect. I still can't clone the latest revised version of the codebase it created to my local computer. Between that and Fly's non-existent documentation, no usage meter of some kind, and the lack of unpaid support (even though I am paying to use the service?) makes me want to avoid Fly, which is unfortunate because I think it does a lot of things right, especially the tunneling and dev experience outside of phoenix.new.

ferfumarma 1y ago

I love everything I read about Phoenix. It's definitely the framework I'm going to use the next time I need to scratch an itch. Having a full stack that is easy to use as a learning sandbox is incredibly helpful in that regard, so this looks amazing.

liampulles 1y ago

This is very cool! I will say though, my spidey senses kick in when looking at stuff like this, and make me wonder about how much I'm going to get vendored in here. Could I use it develop a site off fly.io? If the answer is no, then I'd say this is cool and I think useful for people who need something quick and simple and out of the box, but not something I would ever use on a serious production project.

andy_ppp 1y ago
It’s just producing Elixir/Phoenix code that is stored in GitHub and can be deployed anywhere.
loloquwowndueo 1y ago
The answer is yes. What would you say then? There’s a “clone Git repo” thing in the left side bar, use that to clone the project locally, mix deps.get, mix phx.serve and you’re up. You can deploy this anywhere you want.
- liampulles 1y ago
  If the DB, Auth libraries and such are not tied to fly.io, then yep that's cool. Happy

kuon 1y ago

I really wish I could move to those nice new editors, but as a vim user I just feel paralyzed when I cannot use vim bindings. And all "emulations" I tried are just incomplete.

timeinput 1y ago
I'm with you. I'm going to try Zed in the next couple days based on the response to my comment here. https://news.ycombinator.com/item?id=44322560 https://news.ycombinator.com/item?id=44322560 . I'm stuck with vim. My fingers nearly only work vim, but I managed to move to neovim, which worked. Maybe (something else) can work too.
loloquwowndueo 1y ago
You can pull the repo, tweak it locally with Vim, push it back and ask the LLM to work on top of that. No need to use the built in IDE if you don’t like it.
chrismccord 1y ago
as an avid vim user who moved to emacs evil-mode for a better vim than vim, and now who uses vscode with vscode-vim, it pains me to admit a web browser based editor is a better vim than vim. Somehow starts faster and is less kludgey and more scriptable. You can install extensions on phoenix.new, so vim is not a blocker for you. I drive vim emulation in it every day both on desktop app and within phoenix.new. Couldn't use it without it :)
- kuon 1y ago
  My main issue with vim emulation is that you cannot do file management and windows management. In my vim workflow I keep splitting/unsplitting windows and I like to have a file browser I can navigate with vim bindings.

tobyhinloopen 1y ago

My primary concern with Phoenix is how bad it performs in LLMs and I basically went back to Node/React/Rails for LLMs. This is very exciting and I’ll check it out!

josefrichter 1y ago
What you mean by performs bad in LLMs?
- tobyhinloopen 1y ago
  LLMs don’t know Elixir/Phoenix very well
  - josefrichter 1y ago
    Claude Code is pretty proficient in it. Others, not so much. True.
    - tobyhinloopen 1y ago
      Did you consider creating a LLM.txt and some variants for Phoenix? Some libraries have text-based documentation for LLMs which works great in my experience.

artur_makly 1y ago

For us SaaS Founders, GrowthHackers, Product folks, us non-devs.. What are some solid use-cases for it today?

colecut 1y ago

I am a long time php dev who has been interested in learning elixir/phoenix for a while but never quite motivated enough. I saw this and thought, if this doesn't get me to give it a go, nothing will. Less than 45 minutes after signing up for fly.io, I have a multi-room tic tac toe game deployed. https://tic-tac-toe-cyber.fly.dev/ https://tic-tac-toe-cyber.fly.dev/ I had it build the game, opting for a single room at first to see if that worked. Then I had it add multiple rooms on a different git branch in case that didn't work. It worked great. I learned very little about elixir, phoenix, or deploying to fly.io up to this point, and I already have a nice looking app deployed and running. I know a lot of devs will hate that this is possible, and it is up to me now to look at the steps it took to create this and really understand what is happening, which are broken down extremely simply for me... I will do this because I want to learn. I bet a lot of people won't bother to do that. But those people never would have had apps in the first place and now they can. If they are creating fun experiences and not banking apps, I think that is still great. You guys have been releasing amazing things for years only to be poorly replicated in other languages years later.. but you really outdid yourselves here. I'm blown away. edit: is there a way to see how much of my credits were used by building this?

jonahx 1y ago
Was the graphic design created from prompts too? It's surprisingly nice, especially considering you spent 45 minutes on it.
- colecut 1y ago
  I told it that I wanted a two player tic tac toe game. it give me a selection of "styles" and I chose neon retro.. I probably could have been more creative and typed in my own suggestion. Other than that, I said absolutely nothing about how I wanted the layout. It came up with the idea of listing all active games on the homepage, with the number of players in each, all on its own. I went from "I want a two player tic tac toe game" to having one, and then added multiple rooms, and deployed it all in under 45 minutes, with little input other than that..
chrismccord 1y ago

asmodeuslucifer 1y ago

Well of course I have to test it. Disabled on news.ycombinator.com

poisonta 1y ago

Phoenix needs an ActiveRecord-like database abstraction layer. Many Rails developers try Phoenix at some point because they may need better performance. They’re so accustomed to the Rails structure that they assume Rails has done everything right. However, Ecto and ActiveRecord are two very different beasts. When Rails developers try out Ecto, they often feel there’s too much boilerplate and believe the Rails design is much more intuitive. This, I think, is one reason Phoenix struggles to attract Rails developers. If it can’t please Rails users, it will rarely appeal to others.

lawn 1y ago
The Ash framework is a data abstraction layer you light want to check out, although I'm not familiar with Rails/ActiveRecord to tell if it's closer to what they're after.

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mcdirty 1y ago

Is the site down?

artirdx 1y ago

Mindblowing! This is 100x VB6. The generated UIs are beautiful and professional. I am still trying it out and building an app for tracking expenses but it is working very well. The conversational dialogue it has with the developer is just fantastic. I am amazed at how clear the user experience was in Chris' mind. I am not sure what LLM is being used but this is better experience than any LLM. Given this is first version, I look forward to what comes next! Few issues: 1. The 150 message limit is understable but it suddenly pops up and you lose significant work. I was working on UI mockup and just as I had finished and was ready to go on implementation, this limit appeared and significant part of my work was lost. 2. After the first credit, the credit seems to exhaust pretty fast which makes it expensive, especially when you are trying it out. 3. Also I don't understand when you ask it to prototype different screens, why does it overwrites the same file. 4. It is not able to stop to seek user feedback but keeps trying different approach which kind of exhausts the credit. It would be nice if it describes its approach, so the human developer can provide their feedback. 5. It seems it is using OpenAI because it is often self-congratulatory to the point of being annoying sometimes.

aytigra 1y ago

A bit sad that the language and framework so enjoyable to write an read will be mostly hidden in a coding box. And thinking about it made me realize that soon there will be a completely different programming language used solely by coding agents. ChatGPT gives an interesting take on this, "The fundamental shift is that such a language wouldn’t be written or read, but reasoned about and generated. It would be more like an interlingua between symbolic goals and executable semantics, verbose, unambiguous, self-modifying, auto-verifiable, evolving alongside the agents that use it").