Anthropic acquires Bun

https://bun.com/blog/bun-joins-anthropic

by ryanvogel • 8 months ago

2192 1058 8 months ago

bun.com

ChrisArchitect• 8 months ago

Associated Anthropic post: https://www.anthropic.com/news/anthropic-acquires-bun-as-cla...

colesantiago• 8 months ago

Is Claude Code the first CLI tool to have a $1BN ARR?

CSSer2• 8 months ago

I don't know for sure, but it's definitely the first tool of that value to have a persistent strobing (scroll position) bug so bad that passersby ask me if I'm okay when they see it.

epiccoleman• 8 months ago

Man, I had never even put words to that problem but you are right that it is beyond annoying. It seems to me like it worsens the longer the Claude instance has run - I don't seem to see it early in the session.

jedixit• 8 months ago

This graph from the SemiAnalysis blog suggests that GitHub Copilot reached it earlier this year: https://substackcdn.com/image/fetch/$s_!BGEe!,f_auto,q_auto:...

simonw28• 8 months ago

"GitHub Copilot" encompasses so many different products now that it's hard to see it as a CLI tool.

fragmede2• 8 months ago

Terraform gets to $600mm if you squint really hard make up stuff. Kubectl though. Whatever you want to say about kubernetes complexity, it does get a bunch of money run through it. We could also look at aws-cli, gcloud and az, and if we assign cloud budgets that get run through there, I'm sure it's in the hundreds of millions. Then there's git. Across the whole ecosystem, there's probably a cool couple billion floating through there. gh is probably much smaller. Other tools like docker and ansible come to mind, though those are not quite as popular. Cc only hits $1B ARR if you squint really hard in the first place, so I think in this handwavy realm, I'd say aws-cli comes first, then kubectl, then git, with maybe docket and terraform in the mix as well. Nonetheless, Claude is a really awesome cli tool that I use most days, I find.

theflyinghorse• 8 months ago

Congratulations to the bun team!

victorbuilds• 8 months ago

I use Claude Code CLI daily - it's genuinely changed how I work. The $1B number sounds crazy but honestly tracks with how good the tool is. Curious how Bun integration will show up in practice beyond the native installer.

Aeolun8• 8 months ago

Doesn’t sound crazy at all? My Max subscription costs me more than all the other netflix/spotify etc combined, but I pay it happily, and spotify would go before Claude does.

slig• 8 months ago

Love bun! Congratulations!

re-thc3• 8 months ago

Congrats...

Long-term stability. a home and resources so people can safely bet their stack on Bun.

Isn't it the opposite? Now we've tied Bun to "AI" and if the AI bubble or hype or whatever bursts or dies down it'd impact Bun.

We had over 4 years of runway to figure out monetization. We didn't have to join Anthropic.

There's honestly a higher chance of Bun sticking out that runway than the current AI hype still being around.

Nothing against Anthropic but with the circular financing, all the debt, OpenAI's spending and over-valuations "AI" is the riskier bet than Bun and hosting.

ricopags• 8 months ago

I say don't muddy the water with the public panic over "will it won't it" bubble burst predictions.

The effective demand for Opus 4.5 is bottomless; the models will only get better.

People will always want a code model as good as we have now, let alone better.

Bun securing default status in the best coding model is a win-win-win

re-thc3• 8 months ago

I say don't muddy the water with the public panic over "will it won't it" bubble burst predictions.

It does matter. The public ultimately determines how much they get in funding if at all.

The effective demand for Opus 4.5 is bottomless; the models will only get better.

The demand for the Internet is bottomless. Doesn't mean Dotcom didn't crash.

There are lots of scenarios this can play out, e.g. Anthropic fails to raise a certain round because money dried up. OpenAI buys Anthropic but decides they don't need Bun and closes out the project.

pzo2• 8 months ago

Opus 4.5 is not living in vacuum. It’s the most expensive of models for coders and there is Gemini 3 pro - with many discounts and deepseek 3.2 that is 50x cheaper and not much behind.

phantasmish2• 8 months ago

Yeah, no reader of tech news will take an acquisition of a company with four years of runway as anything but decreasing the odds their product will still be around (and useful to the same audience…) in four years. Even without being tied to a company with lots of exposure to a probable bubble.

supern0va2• 8 months ago

How so? Presumably Jarred got a nice enough payout that if Anthropic failed, he would not need to work. At that point, he's more than welcome to take the fully MIT licensed Bun and fork it to start another company or just continue to work on it himself if he so chooses.

Lermatroid• 8 months ago

Yeah that’s the main part that puzzled me, super happy for the team that they got a successful exit, but I wouldn’t really consider Anthropic’s situation to be stable…

jedahan• 8 months ago

qsort• 8 months ago

Anthropic? The AI people?

jsheard2• 8 months ago

Look, if a terminal emulator can raise $67 million by riding the AI hypewave then a Javscript runtime can do the same. Nobody ever said that AI investments and acquisitions have to make any sense.

jackblemming• 8 months ago

The Bun team works hard, glad to see it pay off.

tkel• 8 months ago

Oh no ... unfortunately this likely means a Bun.AI API in my JS runtime.

afavour3• 8 months ago

What matters: it's staying open source and MIT licensed. I sincerely hope it stays that way. Congrats to the Bun team on making a great tool and getting the recognition they deserve.

Being part of Anthropic gives Bun: Long-term stability.

Let's see. I don't want to always be the downer but the AI industry is in a state of rapid flux with some very strong economic headwinds. I wouldn't confidently say that hitching your wagon to AI gives you long term stability. But as long as the rest of us keep the ability to fork an open source project I won't complain too much.

(for those who are disappointed: this is why you stick with Node. Deno and Bun are both VC funded projects, there's only one way that goes. The only question is timeline)

cortesoft• 8 months ago

Nothing gives you long term stability in tech. You have to constantly work at staying stable, and it isn't always up to anything the company is in control of, no matter what ownership they have.

afavour3• 8 months ago

Nothing gives you long term stability in tech.

Sure. But everything is relative. For instance, Node has much more likelihood of long term stability than Bun, given its ownership.

pelagicAustral• 8 months ago

Godspeed. Seems like a good pairing. Bun is sort of the only part of the JS ecosystem I like, and Code has become such an important tool for my work, that I think good things will come out of this match. Go Bundler as well.

wiseowise4• 8 months ago

Hope nobody buys Astral or Python is f*cked.

zelphirkalt2• 8 months ago

Then it would probably be back to Poetry. Or some other newcomer, or maybe a fork of uv.

andrewl-hn3• 8 months ago

Honestly, given the constant rollercoaster of version management and building tools for Python the move to something else would be expected rather than surprising.

I’ve seems like a great tool, but I remember thinking the same about piping, too.

baq4• 8 months ago

If you froze uv today it’ll take years for anything to get to a state where the switch would be worth it.

simonw28• 8 months ago

uv is very forkable - dual-licensed under Apache and MIT, high quality codebase, it's Rust rather than Python but the Python community has an increasing amount of Rust experience these days.

That's why I'm not personally too nervous about the strategic risk to the Python community of having such a significant piece of the ecosystem from a relatively young VC-backed company.

whalesalad• 8 months ago

Our entire business runs on Python without a drop of Astral in the mix. No one would even notice.

snapcaster• 8 months ago

you should try uv, really impressive tool

Philpax• 8 months ago

Finally, an event capable of killing the Python demon!

thevillagechief• 8 months ago

I don't want to even think about it. uv has been a revelation!

trollbridge• 8 months ago

#1, uv is open-source and it could easily be forked and kept up to date.

#2, if you don't like uv, you can switch to something else.

uv probably has the least moat around it of anything. Truly a meritocracy: people use it because it's good, not because they're stuck with it.

pjmlp11• 8 months ago

Never used any of their tools.

Python is doing great, other than still doing baby steps into having a JIT in CPython.

mrcwinn• 8 months ago

Congrats. This is the first time I remember reading a genuine, authentic story about a sale. Much preferred over “this is about continuing the mission until my earn-out is complete.”

jjordan• 8 months ago

I don't really see how Bun fits as an acquisition for an AI company. This seems more like "we have tons of capital and we want to buy something great" than "Bun is essential to our core business model".

nurumaik• 8 months ago

Looks like they are acquiring the team rather than the product

simonw28• 8 months ago

No, they're clearly acquiring the technology. They're betting Claude Code on Bun, they have an invested interest in the health of Bun.

gkoberger2• 8 months ago

If Anthropic wants to own code development in the future, owning the full platform (including the runtime) makes sense.

Programming languages all are a balance between performance/etc and making it easy for a human to interact with. This balance is going to shit as AI writes more code (and I assume Anthropic wants a future where humans might not even see the code, but rather an abstraction of it... after all, all code we look at is an abstraction on some level).

singularity2001• 8 months ago

   "the full platform"

there are more languages than ts though?

Acquisition of Apple Swift division incoming?

Kwpolska• 8 months ago

They will own it, and then what? Will Claude Code end every response with "by the way, did you know that you can switch to bun for 21.37x faster builds?"

hobofan• 8 months ago

Even outside of code development, Anthropic seems to be very strongly leaning into code interpreter over native tool calling for advancing agentic LLM abilities (e.g. their "skills" approach). Given that those necessitate a runtime of sorts, owning/having access to a runtime like Bun that could e.g. allow them to very seamlessly integrate that functionality into their products better, this acquisition doesn't seem like the worst idea.

BoorishBears3• 8 months ago

It doesn't make sense, and you definitely didn't say why it'd make sense... but enough people are happy enough to see the Bun team reach an exit (especially one that doesn't kill Bun) that I think the narrative that it makes sense will win out.

I see it as two hairy things canceling out: the accelerating trend of the JS ecosystem being hostage to VCs and Rauch is nonsensical, but this time a nonsensical acquisition is closing the loop as neatly as possible.

(actually this reminds me of Harry giving Dobby a sock: on so many levels!)

sankalpmukim• 8 months ago

Does this acquisition mean Claude Code the CLI is more valuable than entiriety of Bun?

gehsty• 8 months ago

It certainly generated more revenue, so this is not surprising?

simonw28• 8 months ago

Claude Code has an annual run rate of $1bn. Bun currently has an annual run rate of $0.

throwaway2902• 8 months ago

No, just that people who borrowed bun 7 million dollars want some of it back...

rvz3• 8 months ago

It does actually.

Claude Code is a 1B+ cash machine and Anthropic directly uses Bun for it.

Acquiring Bun lowers the risk of the software being unmaintained as Bun made $0 and relied on VC money.

Makes sense, but this is just another day in San Francisco of a $0 revenue startup being bought out.

logsr4• 8 months ago

Claude Code running on Bun is an obvious justification, but Buns features (high performance runtime, fast starts, native TS) are also important for training and inference. For instance, in inference you develop a logical model in code that maps to a reasoning sequence, and then execute the code to validate and refine the model, then use this to inform further reasoning. Bun, which is highly integrated and highly focused on performance, is an ideal fit for this. Having Bun in house means that you can use the feedback from all of automation driven execution of Bun to drive improvements to its core.

myth_drannon• 8 months ago

First major success story for Zig language? (Not trying to diminish Bun's team success)

Uninen• 8 months ago

I'd say Ghostty is a pretty big success story as well.

Cieric2• 8 months ago

Let's not forget about TigerBeetle either. They weren't bought (as far as I'm aware), but they seem to have some pretty good backing from customers.

smileson2• 8 months ago

Makes sense, I had idea how else the investors would have made money on a javascript bundler/jsc frontend

ymsodev• 8 months ago

This somewhat answers the question of "how on earth is a JS runtime company going to profit?"

iyn• 8 months ago

Curious about the deal value/price — any clues whether it was just to make existing investors even (so say up to $30M) or are we talking some multiple? But if it's a multiple, even 2x sounds a bit crazy.

dustingetz• 8 months ago

i don’t get it either - bun being the foundation of tons of AI tools is like a best possible outcome, what were they hoping for when they raised the money? Or is this just an admission of “hey, that was silly, we need to land this however we can”? Or do they share major investors and the therefore this is just a consolidation? (Edit: indeed, KP did indeed invest $100M in Anthropic this year. I’m also confused - article states Bun raised 26M but the KP seed round was 7, did they do the A too but unannounced? Notably, the seed was summer 2022 and chatgpt was Nov 30, so the world is different, did the hypothesis change?)

jtokoph• 8 months ago

One option is that the current Bun shareholders didn't see a profitable future and didn't even care if they were made even and a return of the remaining cash was adequate.

Another option is that this was an equity deal where Bun shareholders believe there is still a large multiple worth up potential upside in the current Anthropic valuation.

Plus many other scenarios.

moralestapia• 8 months ago

What?

Why?

tibbydudeza• 8 months ago

Reminds me of Atlassian buying an AI browser.

heinekan• 8 months ago

I’m curious to what the acquisition price was. Bun said they’ve raised $26 million so I’m assuming the price tag has to be a lot higher than that for investors to agree to an acquisition.

yanis_t• 8 months ago

I don't get it. Why would Anthropic need to own a JS runtime?

simonw28• 8 months ago

Because they have a product that makes $1bn+ a year that depends on having a good, stable, cross-platform JS runtime.

LunaSea4• 8 months ago

You're describing Node.js which has existed for the last 15 years

krashidov2• 8 months ago

I'm still confused. Why not just pour a ton of resources into it since it's open source. I guess dev mindshare? It is a great product

sneak• 8 months ago

That doesn’t require or benefit from acquiring Bun. Node continues to exist and serve fine.

altmanaltman7• 8 months ago

but they are a company that burns billions every year in losses and this seems like a pretty random acquisition.

Bun is the product that depends on providing that good, stable, cross-platform JS runtime and they were already doing a good job. Why would Anthropic's acquisition of them make them better at what they were already doing?

pzo2• 8 months ago

Ok but node is even more stable and mature - compare node api parity in bun and also issue of bun vs node

baq4• 8 months ago

Why would Sun then Oracle own Java? Why would Microsoft own .net? Why would Apple own swift?

IOW look where the puck is going.

fprotthetarball• 8 months ago

I'm wondering if Bun would be a good embedded runtime for Claude to think in. If it does sandboxing, or if they can add sandboxing, then they can standardize on a language and runtime for Claude Code and Claude Desktop and bake it into training like they do with other agentic things like tool calls. It'd be too risky to do unless they owned the runtime.

Tiberium4• 8 months ago

As someone who have been using Deno for the last few years, is there anything that Bun does better? Bun seems to use a different runtime (JSC) which is less tested than V8, which makes me assume it might perform worse in real-world tasks (maybe not anymore?). The last time I checked Bun's source code, it was... quite messy and spaghetti-like, plus Zig doesn't really offer many safety features, so it's not that hard to write incorrect code. Zig does force some safety with ReleaseSafe IIRC, but it's still not the same as even modern C++, let alone Rust.

I'll admit I'm somewhat biased against Bun, but I'm honestly interested in knowing why people prefer Bun over Deno.

ecares• 8 months ago

It has wayyyyy better nodejs compatibility (day 1 goal)

Tiberium4• 8 months ago

As far as I know, modern Node compat in Deno is also quite great - I just import packages via 'npm:package' and they work, even install scripts work. Although I remember that in the past Deno's Node compat was worse, yes.

0x457• 8 months ago

Pretty sure one of the Deno day 1 goals was to correct mistakes made during the early days of Node.js.

TheFlyingFish• 8 months ago

I haven't used Deno, but I do use Bun purely as a replacement for npm. It does the hard-linking thing that seems to be increasingly common for package managers these days (i.e. it populates your local node_modules with a bunch of hard links to its systemwide cache), which makes it vastly quicker and more disk-efficient than npm for most usage.

Even with a cold cache, `bun install` with a large-ish dependency graph is significantly faster than `npm install` in my experience.

I don't know if Deno does that, but some googling for "deno install performance vs npm install" doesn't turn up much, so I suspect not?

As a runtime, though, I have no opinion. I did test it against Node, but for my use case (build tooling for web projects) it didn't make a noticeable difference, so I decided to stick with Node.

homebrewer• 8 months ago

pnpm does all that on top of node. Also disables postinstall scripts by default, making the recent security incidents we've seen a non-issue.

satvikpendem6• 8 months ago

Deno does all that. Hell, yarn does too, or pnpm as the sibling mentioned.

agumonkey2• 8 months ago

IIRC bun zig code base has a lot of fine optimization too. I think the lead did a conference explaining his work. Or maybe i'm confused.

WorldMaker3• 8 months ago

Deno does that. It also refrains from keeping a local node_modules at all until/unless you explicitly ask it to for whatever compatibility reason. There are plugins to things like esbuild to use the Deno resolver and not need a node_modules at all (if you aren't also using the Deno-provided bundler for whatever reason such as it disappeared for a couple versions and is still marked "experimental").

user34283• 8 months ago

I decided to stick with Node in general. I don't see any compelling reason to change it.

Faster install and less disk space due to hardlink? Not really all that important to me. Npm comes with a cache too, and I have the disk space. I don't need it to be faster.

With the old-school setup I can easily manually edit something in node_modules to quickly test a change.

No more node_modules? It was a cool idea when yarn 2 initially implemented it, but at the end of the day I prefer things to just work rather than debug what is and isn't broken by the new resolver. At the time my DevOps team also wasn't too excited about me proposing to put the dependencies into git for the zero-install.

cesarvarela• 8 months ago

I've found it to be at least twice as fast with practically no compat issues.

smarnach4• 8 months ago

Twice as fast at executing JavaScript? There's absolutely zero chance this is true. A JavaScript engine that's twice as fast as V8 in general doesn't exist. There may be 5 or 10 percent difference, but nothing really meaningful.

FragenAntworten• 8 months ago

Easily bundling and serving frontend code from your backend code is very appealing: https://bun.com/docs/bundler/fullstack

Despite the page title being "Fullstack dev server", it's also useful in production (Ctrl-F "Production Mode").

gre• 8 months ago

I had memory leaks in bun and not in deno or node for the same code. ymmv

kenhwang2• 8 months ago

I always figured Bun was the "enterprise software" choice, where you'd want to use Bun tools and libraries for everything and not need to bring in much from the broader NPM library ecosystem.

Deno seems like the better replacement for Node, but it'd still be at risk of NPM supply chain attacks which seems to be the greater concern for companies these days.

skybrian5• 8 months ago

If you want to download open source libraries to be used in your Bun project then they will come from npm, at least by default. [1].

So it seems odd to say that Bun is less dependent on the npm library ecosystem.

[1] It’s possible to use jsr.io instead: https://jsr.io/docs/using-packages

gr4vityWall2• 8 months ago

I'll admit I'm somewhat biased against Bun?

Why? Genuine question, sorry if it was said/implied in your original message and I missed it.

Tiberium4• 8 months ago

Good question, hard to say, but I think it's mainly because of Zig. At its core Zig is marketed as a competitor to C, not C++/Rust/etc, which makes me think it's harder to write working code that won't leak or crash than in other languages. Zig embraces manual memory management as well.

fn-mote• 8 months ago

I mean, they said they looked at the source code and thought it was gross, so there’s a justification for their concern, at least.

satvikpendem6• 8 months ago

Search for pointer exceptions or core dumps on Bun's GitHub issues and you'll see why people (should) use Deno over Bun, if only because Rust is a way more safe language than Zig.

reactordev6• 8 months ago

This is a non sequitur. Both Rust and Zig and any other language has the ability to end in an exception state. Whether it be kernel exception, pointer exception, or Rust's panic! - these things exist.

The reason why you see so many GitHub issues about it is because that's where the development is. Deno is great. Bun is great. These two things can both be great and we don't have to choose sides. Deno has it's use case. Bun has it's. Deno want's to be secure and require permissions. Bun just wants to make clean, simple, projects. This fight between Rust vs The World is getting old. Rust isn't any "safer" when Deno can panic too.

rvrb• 8 months ago

I haven't verified this, but I would be willing to bet that most of Bun's issues here have more to do with interfacing with JavaScriptCore through the C FFI than Zig itself. this is as much a problem in Rust as it is in Zig. in fact, it has been argued that writing unsafe Zig is safer than writing unsafe Rust: https://zackoverflow.dev/writing/unsafe-rust-vs-zig/

skybrian5• 8 months ago

I’ve been using Deno too. Although npm support has improved and it’s fine for me, I think Deno has more of a “rewrite the world” philosophy. For example, they created their own package registry [1] and their own web framework [2]. Bun seems much more focused on preexisting JavaScript projects.

[1] https://jsr.io/ [2] https://fresh.deno.dev/

Tiberium4• 8 months ago

It's interesting that people have directly opposite opinions on whether Deno or Bun are meant to be used with the existing ecosystem - https://news.ycombinator.com/item?id=46125049

bcye4• 8 months ago

It just works. Whatever JavaScript/TypeScript file or dependencies I throw at it, it will run it without needing to figure out CJS or ESM, tsconfig, etc.

I haven't had that experience with deno (or node)

catapart2• 8 months ago

Same. I had a little library I wrote to wrap indexedDB and deno wouldn't even compile it because it referenced those browser apis. I'm sure it's a simple flag or config file property, or x, or y, or z, but the simple fact is, bun didn't fail to compile.

Between that and the discord, I have gotten the distinct impression that deno is for "server javascript" first, rather than just "javascript" first. Which is understandable, but not very catering to me, a frontend-first dev.

pjmlp11• 8 months ago

Agreed, the language would be interesting during the 1990's, nowadays not so much.

The tools that the language offers to handle use after free is hardly any different from using Purify, Insure++ back in 2000.

defen2• 8 months ago

I find comments like this fascinating, because you're implicitly evaluating a counterfactual where Bun was built with Rust (or some other "interesting" language). Maybe Bun would be better if it were built in Rust. But maybe it would have been slower (either at runtime or development speed) and not gotten far enough along to be acquired by one of the hottest companies in the world. There's no way to know. Why did Anthropic choose Bun instead of Deno, if Deno is written in a better language?

silasdavis2• 8 months ago

Stopped following Deno while they were rejecting the need for a package management solution. Used Bun instead.

croes3• 8 months ago

Isn’t because packages are one of the problems deno tried to fix?

spiffytech• 8 months ago

I tried several times to port Node projects to Deno. Each time compatibility had "improved" but I still didn't have a working build after a few days of effort.

I don't know how Deno is today. I switched to Bun and porting went a lot smoother.

Philosophically, I like that Bun sees Node compatibility as an obvious top priority. Deno sees it as a grudging necessity after losing the fight to do things differently.

fastball• 8 months ago

Which makes sense given that a big impetus for Deno's existence was the creator of Node/Deno (Ryan Dahl) wanting to correct things he viewed as design mistakes in Node.

dmit• 8 months ago

is there anything that Bun does better?

Telling prospective employees that if you're not ready to work 60-hour weeks, then what the fuck are you doing here? for one.

Zig does force some safety with ReleaseSafe IIRC

which Bun doesn't use, choosing to go with `ReleaseFast` instead.

yieldcrv• 8 months ago

I've been using Bun since 2022 just to be trendy for recruitment (it worked, and still works despite it almost being 2026)

Bun is fast, and its worked as a drop in replacement for npm in large legacy projects too.

I only ever encountered one issue, which was pretty dumb, Amazon's CDK has hardcoded references to various package manager's lock files, and Bun wasn't one of them

https://github.com/aws/aws-cdk/issues/31753

This wasn't fixed till the end of 2024 and as you can see, only accidentally merged in but tolerated. It was promptly broken by a bun breaking change

https://github.com/aws/aws-cdk/issues/33464

but don't let Amazon's own incompetency be the confirmation bias you were looking for about using a different package manager in production

you can use SST to deploy cloud resources on AWS and any cloud, and that package works with bun

WorldMaker3• 8 months ago

Bun seems to use a different runtime (JSC) which is less tested than V8, which makes me assume it might perform worse in real-world tasks (maybe not anymore?).

JSC is still the JS engine for WebKit-based browsers, especially Safari, and per Apple App Store regulations the only JS engine supposedly allowable in all of iOS.

It's more "mature" than V8 in terms of predating it. (V8 was not a fork of it and was started from scratch, but V8 was designed to replace it in the Blink fork from WebKit.)

It has different performance goals and performance characteristics, but "less tested" seems uncharitable and it is certainly used in plenty of "real-world tasks" daily in iOS and macOS.

torginus3• 8 months ago

Is it just me, but I don't find npm that slow? Sure it's not a speed demon, but I rarely need to do npm install anyways so it's not a bottleneck for me.

For deploy, usually running the attached terraform script takes more time.

So while a speed increase is welcome, but I don't feel it gives me such a boost.

hinkley5• 8 months ago

The speed shows up for large projects. Especially if you end up with multiple node_modules directories in your dev sandbox.

dunham• 8 months ago

Is JSC less tested? I thought it was used in Safari, which has some market share.

I used bun briefly to run the output of my compiler, because it was the only javascript runtime that did tail calls. But I eventually added a tail call transform to my compiler and switched to node, which runs 40% faster for my test case (the compiler building itself).

kabirgoel• 8 months ago

My team has been using it in prod for about a year now. There were some minor bugs in the runtime's implementation of buffers in 1.22 (?), but that was about the only issue we ran into.

The nice things:

1. It's fast.

2. The standard library is great. (This may be less of an advantage over Deno.)

3. There's a ton of momentum behind it.

4. It's closer to Node.js than Deno is, at least last I tried. There were a bunch of little Node <> Deno papercuts. For example, Deno wanted .ts extensions on all imports.

5. I don't have to think about JSR.

The warts:

1. The package manager has some issues that make it hard for us to use. I've forgotten why now, but this in particular bit us in the ass: https://github.com/oven-sh/bun/issues/6608. We use PNPM and are very happy with it, even if it's not as fast as Bun's package manager.

Overall, Deno felt to me like they were building a parallel ecosystem that I don't have a ton of conviction in, while Bun feels focused on meeting me where I am.

creata3• 8 months ago

Looking at Bun's website (the comparison table under "What's different about Bun?") and what people have said here, the only significant benefit of Bun over Node.js seems to be that it's more batteries-included - a bigger standard library, more tools, some convenience features like compiling JSX and stripping TypeScript types on-the-fly, etc.

It's not clear to me why that requires creating a whole new runtime, or why they made the decisions they did, like choosing JSC instead of V8, or using a pre-1.0 language like Zig.

bodge5000• 8 months ago

I really want to like Deno and will likely try it again, but last time I did it was just a bit of a pain anytime I wanted to use something built for npm (which is most packages out there), whereas bun didn't have that problem.

There's certainly an argument to be made that, like any good tool, you have to learn Deno and can't fall back on just reusing node knowledge, and I'd absolutely agree with that, but in that case I wanted to learn the package, not the package manager.

Edit: Also it has a nice standard library, not a huge win because that stuff is also doable in Deno, but again, its just a bit less painless

kamikazechaser• 8 months ago

At this stage I don't think either is better over the other. Deno has inexplicable high memory usage issues in Linux containers. Bun more or less suffers from the same with an added dose of segfaults.

1. https://github.com/denoland/deno/issues?q=is%3Aissue%20state... 2. https://github.com/oven-sh/bun/issues?q=is%3Aissue%20state%3...

Node.js is a no-brainer for anyone shipping a TS/JS backend. I'd rather deal with poor DX and slightly worse performance than risk fighting runtime related issues on deployment.

Linux needs to be a first class citizen for any runtime/langauge toolchain.

Griffinsauce• 8 months ago

Crash. According to my experience trying it many times oves the past years.

It feels like a very unfocused project, every few months they introduce a new feature that is to replace an entire class of tools, while the original promise of "drop in Node replacement" was never fulfilled (or at least, that was the vibe for the past years when I was still paying attention).

We'll see how this works out but speed + lack of scope never works out well in the long term.

kylecarbs• 8 months ago

Bun has completely changed my outlook on the JS ecosystem. Prior to Bun, there was little focus on performance. Now the entire space rallies around it.

Congrats to Jarred and the team!

nailer• 8 months ago

One important original point of node was that v8 made JS very fast by compiling to machine code, plus it’s had multithreading built in for a decade.

whizzter• 8 months ago

Machine code yes (along with Spidermonkey, JSC and Nashorn), the timeframe around 2005-2010 saw the introduction of JIT'ed JS runtimes. Back then however JS was firmly single-threaded, it was only with the introduction of SharedArrayBuffer that JS really started to receive multithreading features (outside of SharedArrayBuffer and other shareable/sendable types, a runtime could opt to run stuff like WebWorkers/WebAudioWorkers in separate processes).

Early Node f.ex. had a multi-process setup built in, Node initially was about pushing the async-IO model together with a fast JS runtime.

Why Bun (and partially Deno) exists is because TypeScript helps so damn much once projects gets a tad larger, but usage with Node hot-reloading was kinda slow, multiple seconds from saving a file until your application reloads. Even mainline node nowadays has direct .ts file loading and type erasing to quicken the workflow.

stefan_• 8 months ago

That is the most absurd thing I've heard in 20 years. Chrome literally was launched on performance, for JS and beyond.

The reality is that the insane "JS ecosystem" will rally around whatever is the latest hotness.

satvikpendem6• 8 months ago

That's because it's not written in JS at all but a compiled systems language, no wonder it's gonna be fast.

denismenace• 8 months ago

Virtually all JavaScript engines are written in compiled languages. (Most runtimes for that matter nut just JS)

krig5• 8 months ago

Prior to Bun, there was little focus on performance.

This is just completely insane. We went through more than a decade of performance competition in the JS VM space, and the _only_ justification that Google had for creating V8 was performance.

The V8 engine was first introduced by Google in 2008, coinciding with the launch of the Google Chrome web browser. At the time, web applications were becoming increasingly complex, and there was a growing need for a faster, more efficient JavaScript engine. Google recognized this need and set out to create an engine that could significantly improve JavaScript performance.

I guess this is the time we live in. Vibe-coded projects get bought by vibe-coded companies and are congratulated in vibe-coded comments.

logsr4• 8 months ago

Vibe-coded projects get bought by vibe-coded companies

this is so far from the truth. Bun, Zig, and uWebsockets are passion projects run by individuals with deep systems programming expertise. furthest thing from vibe coding imaginable.

a decade of performance competition in the JS VM space

this was a rising tide that lifted all boats, including Node, but Node is built with much more of the system implemented in JS, so it is architecturally incapable of the kind of performance Bun/uWebsockets achieves.

tibbar• 8 months ago

This missed the mark - Bun optimized systems whose predecessors were often implemented as JS libraries with a high number of syscalls. V8 is super fast for web usecases but your typical webpack / react compiler as implemented in JS had tons of unnecessary bottlenecks.

umanwizard2• 8 months ago

Prior to Bun, there was little focus on performance

v8 is one of the most advanced JIT runtimes in the world. A lot of people have spent a lot of time focusing on its performance.

renewiltord• 8 months ago

Hahaha congratulations. This is amazing. The most unlikely outcome for a devtools team. Fascinating stuff.

This is promising for Astral et al who I really like but worried about their sustainability. It does point to being as close to the user as possible mattering.

andrewl-hn3• 8 months ago

I’ll be honest, while I have my doubts about the match of interests and cohesion between an AI company and a JS runtime company I have to say this is the single best acquisition announcement blog post I’ve seen in 20 years or so.

Very direct, very plain and detailed. They cover all the bases about the why, the how, and what to expect. I really appreciate it.

Best of luck to the team and hopefully the new home will support them well.

raw_anon_11116• 8 months ago

But how is another company that is also VC backed and losing money providing stability for Bun?

How long before we hear about “Our Amazing Journey”?

On the other hand, I would rather see someone like Bun have a successful exit where the founders seem to have started out with a passion project, got funding, built something out they were excited about and then exit than yet another AI company by non technical founders who were built with the sole purpose of getting funding and then exit.

simonw28• 8 months ago

Anthropic may be losing money, but a company with $7bn revenue run rate (https://www.anthropic.com/news/statement-dario-amodei-americ...) is a whole lot healthier than a company with a revenue of 0.

rvnx2• 8 months ago

Often it happens that VCs buy out companies from funds belonging to a fresh because the selling fund wants to show performance to their investors until "the big one", or move cash one from wealthy pocket to another one.

"You buy me this, next time I save you on that", etc...

"Raised $19 million Series A led by Khosla Ventures + $7 million"

"Today, Bun makes $0 in revenue."

Everything is almost public domain (MIT) and can be forked without paying a single dollar.

Questionable to claim that the technology is the real reason this was bought.

nathan-wall• 8 months ago

But how is another company that is also VC backed and losing money providing stability for Bun?

Reminds me of when Tron, the crypto company, bought BitTorrent.

lacker• 8 months ago

The real risk is not that Anthropic will run out of money, but that they will change their strategy to something that isn't Bun-based, and supporting Bun won't make sense for them any more.

kelvinjps102• 8 months ago

I misread Amazon, implying that Amazon might buy Anthropic, and I think that's what will end up happening.

moritzwarhier• 8 months ago

Ditto, and I got to know Bun via HN. It seemed intriguing, but also "why another JS runtime" etc.

If Bun embraces the sweet spot around edge computing, modern JS/TS and AI services, I think their future ahead looks bright.

Bun seems more alive than Deno, FWIW.

jjcm• 8 months ago

One thing I like about this, despite it meaning Bun will be funded, is Anthropic is a registered public benefit corporation. While this doesn't mean Anthropic cant fuck over the users of Bun, it at least puts in some roadblocks. The path of least-resistance here should be to improve Bun for users, not to monetize it to the point where it's no longer valuable.

echelon• 8 months ago

Anthropic is a registered public benefit corporation

Does that mean anything at all?

OpenAI is a public benefit corporation.

laserbeam• 8 months ago

I admit, it is a good acquisition announcement. I can’t remember the last acquisition announcement that was kept for more than 1-2 years. Leadership changes, priorities shift…

juddlyon• 8 months ago

I had the same impression: bottom line up front, didn’t bury the lede, no weasel language.

ctoth• 8 months ago

This decision is honestly very confusing to me as a constant user of Claude Code (I have 3 of them open at the moment.)

So many of the issues with it seem to be because ... they wrote the damn thing in JavaScript?

Claude is pretty good at a constrained task with tests -- couldn't you just port it to a different language? With Claude?

And then just ... the huge claude.json which gets written on every message, like ... SQLite exists! Please, please use it! The scrollback! The Keyboard handling! Just write a simple Rust or Go or whatever CLI app with an actual database and reasonable TUI toolkit? Why double down and buy a whole JavaScript runtime?

mccoyb• 8 months ago

Boggles the mind.

dboon3• 8 months ago

Ink (and modern alternatives) probably are the best TUI toolkit. If you want to write a UI that's genuinely good, you need e.g. HTML, or some way to express divs and flex box. There isn't really another way to build professional grade UIs; I love immediate mode UI for games, but the breadth of features handled by the browser UI ecosystem is astonishing. It is a genuinely hard problem.

And if you're expressing hierarchical UI, the best way to do it is HTML and CSS. It has the richest ecosystem, and it is one of the most mature technologies in existence. JS / TS are the native languages for those tools. Everything is informed by this.

Of course, there are other options. You could jam HTML and CSS into (as you mention) Rust, or C, or whatever. But then the ecosystem is extremely lacking, and you're reinventing the wheel. You could use something simpler, like QML or handrolled. But then you lose the aforementioned breadth of features and compatibilities with all the browser code ever written.

TypeScript is genuinely, for my money, the best option. The big problem is that the terminal backends aren't mature (as you said, scrollback, etc). But, given time and money, that'll get sorted out. It's much easier to fix the terminal stuff than to rewrite all of the browser.

frumplestlatz4• 8 months ago

The idea that you need or want HTML or CSS to write a TUI is missing the entire point of what made TUIs great in the first place. They were great precisely because they were clean, fast, simple, focused -- and didn’t require an entire web stack to draw colored boxes.

EMM_386• 8 months ago

Ink seems to be the root cause of a major issue with the Claude Code CLI where it flickers horribly when it needs to repeatedly clear the screen and redraw.

I don't know why it's even necessary for this.

https://github.com/atxtechbro/test-ink-flickering

Issue on Claude Code GitHub:

https://github.com/anthropics/claude-code/issues/769

morshu90015• 8 months ago

I like JS for this use case, and React on web, but really not fond of the Ink usage. Idk if it's Ink itself or the way it gets used, but somehow people are making CLIs that lag and waste terminal space now.

frumplestlatz4• 8 months ago

I have to admit this was my first thought, too. I'm pretty obsessed with Claude Code, but the actual app is so incredibly poorly engineered for something that doesn't even do that much.

Rust, Go, whatever -- writing a good TUI isn't that hard of a problem. Buying an entire VC funded JS runtime company isn't how you solve it.

rprend2• 8 months ago

“Port it to a different language” a language that’s more out of distribution? Bad devex. Store data as an unreadable binary file? Bad devex.

Stay in distribution and in the wave as much as possible.

Good devex is all you need. Claude code team iterates and ships fast, and these decisions make total sense when you realize that dev velocity is the point.

asim• 8 months ago

It's more honest than the Replicate answer but I think inevitably if you can't raise the next round and you get distracted by the shiny AI that this is the path taken by many teams. There is absolutely nothing wrong with that. There was an exuberant time when all the OSS things were getting funded, and now all AI things get funded. For many engineer founders, it's a better fit to go build deep technical stuff inside a bigger company. If I had that chance I would probably have taken it too. Good luck to the Bun team!

copperroof• 8 months ago

Well this just created a lot of work for me. Everything’s turning to shit at an alarming rate.

torben-friis• 8 months ago

If most new code is going to be written, tested, and deployed by AI agents

That perspective following “in two-three years” makes me shudder, honestly.

mritchie7122• 8 months ago

At the time of writing, Bun's monthly downloads grew 25% last month (October, 2025), passing 7.2 million monthly downloads. We had over 4 years of runway to figure out monetization. We didn't have to join Anthropic.

I believe this completely. They didn't have to join, which means they got a solid valuation.

Instead of putting our users & community through "Bun, the VC-backed startups tries to figure out monetization" – thanks to Anthropic, we can skip that chapter entirely and focus on building the best JavaScript tooling.

I believe this a bit less. It'll be nice to not have some weird monetization shoved into bun, but their focus will likely shift a bit.

drakythe• 8 months ago

Given the worries about LLM focused companies reaching profitability I have concerns that Bun's runway will be hijacked... I'd hate for them to go down with the ship when the bubble pops.

Karrot_Kream4• 8 months ago

This is my fear. It's one thing to lose a major sponsor. It's another to get cut due to a focus on profitability later down the line.

someguyiguess14• 8 months ago

At least Anthropic itself has the stated goal of creating ethical AI that benefits humanity. That’s more than can be said for any other AI companies. Time will tell though. Google‘s motto used to be “don’t be evil” and now it’s basically the opposite.

serial_dev2• 8 months ago

I believe this a bit less.

They weren’t acquired and got paid just to build tooling as before and now completely ignoring monetization until the end of times.

velcrovan• 8 months ago

Maybe they were though. Maybe Anthropic just wanted to bring a key piece of the stack in-house.

ambicapter• 8 months ago

Good for them, could be bad for actual users.

n2d42• 8 months ago

    > They didn't have to join, which means they got a solid valuation.

This isn't really true. It's more about who wanted them to join. Maybe it was Anthropic who really wanted to take over Bun/hire Jarred, or it was Jarred who got sick of Bun and wanted to work on AI.

I don't really know any details about this acquisition, and I assume it's the former, but acquihires are also done for other reasons than "it was the only way".

n2d42• 8 months ago

Can't edit my comment anymore but Bun posted a pretty detailed explanation of their motivation here: https://bun.com/blog/bun-joins-anthropic

Sounds like "monetizing Bun is a distraction, so we're letting a deep-pocketed buyer finance Bun moving forward".

Karrot_Kream4• 8 months ago

They didn't have to join, which means they got a solid valuation.

Did they? I see a $7MM seed round in 2022. Now to be clear that's a great seed round and it looks like they had plenty of traction. But it's unclear to me how they were going to monetize enough to justify their $7MM investment. If they continued with the consultancy model, they would need to pay back investors from contracts they negotiate with other companies, but this is a fraught way to get early cashflow going.

Though if I'm not mistaken, Confluent did the same thing?

robertjpayne2• 8 months ago

They had a second round that was $19m in late 2023. I don't doubt for a second that they had a long runway given the small team.

someguyiguess14• 8 months ago

Good thing they got acquired by a company that also has a snowballs chance in hell of ever paying back their investment

papichulo2023• 8 months ago

Anthropic is still a new company and so far they seem "friendly". That being said, I still feel this can go either way.

VerifiedReports5• 8 months ago

Yep. Remember when "Open"AI took a bunch of grant money and then turned for-profit?

And kept their fraudulent name.

ojosilva• 8 months ago

Yeah, now they are part of Anthropic, who haven't figured out monetization themselves. Shikes!

I'm a user of Bun and an Anthropic customer. Claude Code is great and it's definitely where their models shine. Outside of that Anthropic sucks,their apps and web are complete crap, borderline unusable and the models are just meh. I get it, CC's head got probably a powerplay here given his department is towing the company and his secret sauce, according to marketing from Oven, was Bun. In fact VSCode's claude backend is distributed in bun-compiled binary exe, and the guy is featured on the front page of the Bun website since at least a week or so. So they bought the kid the toy he asked for.

Anthropic needs urgently, instead, to acquire a good team behind a good chatbot and make something minimally decent. Then make their models work for everything else as well as they do with code.

JimDabell2• 8 months ago

Yeah, now they are part of Anthropic, who haven't figured out monetization themselves.

Anthropic are on track to reach $9BN in annualised revenue by the end of the year, and the six-month-old Claude Code already accounts for $1BN of that.

someguyiguess14• 8 months ago

How is their Web app any different than any other AI? I feel like it’s on par with all of them. It works great for me. Although I mostly use Claude code.

nrhrjrjrjtntbt2• 8 months ago

"We were maybe gonna fuck ya, buy now we promise we wont"

gjvc• 8 months ago

apart from the unfortunate typo, this is accurate.

like when a political leader says they have full faith in one of their ministers, you know said minister will be gone by next week.

a-dub• 8 months ago

they acquihired the team and derisked their investment in building claude code on top of bun. makes sense to me.

moreover, now they can make investments in order to make it an an even more efficient and secure runtime for model workspaces.

ptak• 8 months ago

What a trip. Love both, so all good I guess.

mhitza• 8 months ago

This acquisition makes no sense.

Investors must be happy because Bun never had to find out how to become profitable.

baq4• 8 months ago

It’s enough Anthropic finds it profitable to run Claude Code on it.

dboreham2• 8 months ago

This acquisition makes no sense.

except this sense:

Investors must be happy because Bun never had to find out how to become profitable.

odie5533• 8 months ago

But what is the upside for anthropic?

umanwizard2• 8 months ago

Hard to say it makes no sense when you don't know how much they were acquired for. I would guess it is a trivial amount relative to Anthropic's war chest.

zwnow5• 8 months ago

Well not gonna use Bun anymore I guess

jjice• 8 months ago

Why not?

zwnow5• 8 months ago

Because I avoid all major AI players with everything I got as all of them are thieves.

suralind• 8 months ago

Good luck, always worried about stuff like that because it happened so many times and the product got worse eventually. At the same time, ai understand how much effort went into building something like Bun and people need to fund their life's somehow, so there's that.

beanjuiceII• 8 months ago

anthropic wont win, and will just get bought out by an ibm or oracle in the end...time to migrate from bun now

mrweasel• 8 months ago

If Bun ends up at either IBM or Oracle, then it's a pretty safe platform, it could stay around for 50 years.

polskibus• 8 months ago

Wouldn’t it make more sense to write the same functionality using a more performant, no-gc language? Aren’t competitors praised for their CLIs being faster for that reason?

munificent2• 8 months ago

With AI tooling, we are in the era where rapid iteration on product matters more than optimal runtime performance. Given that, implementing your AI tooling in a language that maximizes engineer productivity makes sense, and I believe GC does that.

logsr4• 8 months ago

JS/TS has a fundamental advantage, because there is more open source JS/TS than any other language, so LLMs training on JS/TS have more to work with. Combine that with having the largest developer community, which means you have more people using LLMs to write JS/TS than any other language, and people use it more because it works better, then the advantage compounds as you retrain on usage data.

timeon• 8 months ago

One would expect that "AI tooling" is there for rapid iteration and one can use it with performant languages. We already had "rapid iteration" with GC languages.

kurtis_reed• 8 months ago

Codex is written in Rust

ximeng2• 8 months ago

I use bun in a project but Claude Code always uses node to run throwaway scripts. Maybe they can persuade it to use bun as part of this acquisition?

simlevesque• 8 months ago

I bet CC will become a binary with bun included and it'll use it's internal JS engine to run most scripts.

runjake• 8 months ago

I always tell it to use Bun and it works? Am I misunderstanding?

ximeng2• 8 months ago

It seems the default is node (despite the project docs saying to use bun and all example script documentation using bun). It will use bun if told, but there’s definitely nothing saying to use node and it uses that anyway.

threetonesun• 8 months ago

Oddly I saw it try to use bun the other day, and was confused because everything in the project is in node.

dzonga• 8 months ago

it boils down to - we didn't have full conviction that over the long run we will prove superior to node.js, however a.i company burning a lot of cash, has invested in us by basing their toolchain on us - so they have no option to acquire-hire us.

hu35• 8 months ago

quite the uncharitable take.

On the opposite spectrum it's just that Claude and Bun are great technologies that joined forces.

dboon3• 8 months ago

Incredible news on so, so many levels!

(1) Bun is what technical startups should be. Consistently excellent decisions, hyper focused on user experience, and a truly excellent technical product.

(2) We live in a world where TUIs are causing billion dollar acquisitions. Think about that. Obviously, Bun itself is largely orthogonal to the TUIs. Just another use case. But also obviously, they wouldn't have been acquired like this without this use case.

(3) There's been questions of whether startups like Bun can exist. How will they make money? When will they have to sell out one of the three principles in (1) to do so? The answer seems to be that they don't; at least, not like we expected, and in my opinion not in a sinister way.

A sinister or corrupting sell out would be e.g. like Conan. What started as an excellent tool became a bloated, versioned mess as they were forced to implement features to support the corporate customers that sustained them.

This feels different. Of course, there will be some selling out. But largely the interests of Anthropic seem aligned with "build the best JS runtime", since Anthropic themselves must be laser focused on user experience with Claude Code. And just look at Opencode [^1] if you want to see what leaning all the way into Bun gets you. Single file binary distribution, absurdly fast, gorgeous. Their backend, OpenTUI [^2], is a large part of this, and was built in close correspondence with the Bun folks. It's not something that could exist without Bun, in my opinion.

(4) Anthropic could have certainly let Bun be a third party to which they contributed. They did not have to purchase them. But they did. There is a strange not-quite altruism in this; at worst, a casting off of the exploitation of open source we often see from the biggest companies. Things change; what seems almost altruistic now could be revealed to be sinister, or could morph into such. But for now, at least, it feels good and right.

[^1]: https://github.com/sst/opencode [^2]: https://github.com/sst/opentui

Simran-B• 8 months ago

Classic - brand new blog post:

We’re hiring engineers.

Careers page:

Sorry, no job openings at the moment.

adpirz• 8 months ago

It's the Anthropic careers page that you're likely looking for now:

https://www.anthropic.com/jobs?team=4050633008

prathamtharwani• 8 months ago

Is it just me or does this page keep jumping back to the top when I try to scroll?

antihero2• 8 months ago

Maybe the engineers are Claude agents.

fishmicrowaver4• 8 months ago

My first thought went to how openai used Rust to build their CLI tool and Anthropic's CEO bought influence over Zig as a reaction.

ivanjermakov• 8 months ago

bought influence over Zig as a reaction

Elaborate? I believe Zig's donors don't get any influence and decision making power.

hu35• 8 months ago

That would require them to hire/buy Zig team. Which is not the case.

dkmar• 8 months ago

Jarred just tweeted a few days ago about how little influence over zig he has, funnily enough.

https://x.com/jarredsumner/status/1994950394955665486?s=20

sherbondy• 8 months ago

Congrats Jarred and team! You have saved humanity many hours already, and I'm sure with Anthropic's backing, you will spare us many more. Farewell would-be headaches from Node & NPM tooling and waiting for builds and tests and package updates. Exciting times ahead!

Using bun on a side project reinvigorated my love of software development during a relatively dark time in my life, and part of me wonders if I would have taken the leap onto my current path if it weren't for the joy and feeling of speed that came from working with bun!

giancarlostoro7• 8 months ago

Sounds like the goal is to bundle up Bun with Claude Code insanely tightly, to the point where it doesn't matter if you have nodejs installed locally, but also they can optimize key things for Claude Code's Bun runtime as needed. It's a brilliant acquisition, and bun stays open source, which allows it to continue to grow, to Anthropics benefit and everyone else's.

mpeg• 8 months ago

A nice start would probably be for Claude Code to stop trying to use npm when it detects a bun lockfile and vice versa...

giancarlostoro7• 8 months ago

Yeah Claude is very good, but it definitely needs to get "smarter" in some nuanced areas.

christophilus2• 8 months ago

I just ln bun to npm, npx, and node. This has the added benefit of letting ts_ls and various other tools work without requiring me to have both node and bun installed locally.

mokarma2• 8 months ago

Quote from the CEO of Anthropic in March 2025: "I think we'll be there in three to six months where AI is writing 90% of the code and then in 12 months we may be in a world where AI is writing essentially all of the code"

WhyOhWhyQ• 8 months ago

I actually like claude code, but that was always a risky thing to say (actually I recall him saying their software is 90% AI produced) considering their cli tool is literally infested with bugs. (Or it least it was last time I used it heavily. Maybe they've improved it since.)

johnfn6• 8 months ago

AI writes about 90% of my code.

smcleod10• 8 months ago

Probably about 95% of mine now. Much better than I could for the most part.

pjmlp11• 8 months ago

Only 10% to go for a full replacement.

WesleyJohnson• 8 months ago

What languages and frameworks? What is the domain space you're operating in? I use Cursor to help with some tasks, but mainly only use the autocomplete. It's great; no complaints. I just don't ever see being able to turn over anywhere close to 90% with the stuff we work on.

jsheard2• 8 months ago

Maybe he was correct in the extremely literal sense of AI producing more new lines of code than humans, because AI is no doubt very good at producing huge volumes of Stuff very quickly, but how much of that Stuff actually justifies its existence is another question entirely.

rsyring2• 8 months ago

Do you have a source for the quote?

rglover3• 8 months ago

https://www.youtube.com/watch?v=9Shl1-ZJI6E

mjr002• 8 months ago

Why didn't they just use AI to write their own Bun instead of wasting 8-9 figures on this company? Makes no sense.

fredoliveira• 8 months ago

"Wasting" is doing a lot of work in that sentence.

They're effectively bringing on a team that's been focused on building a runtime for years. The models they could throw at the problem can't be tapped on the shoulder, and there's no guarantee they'd do a better job at building something like Bun.

furyofantares• 8 months ago

From the article, Claude Code is being used extensively to develop Bun already.

Over the last several months, the GitHub username with the most merged PRs in Bun's repo is now a Claude Code bot. We have it set up in our internal Discord and we mostly use it to help fix bugs. It opens PRs with tests that fail in the earlier system-installed version of Bun before the fix and pass in the fixed debug build of Bun. It responds to review comments. It does the whole thing.

You do still need people to make all the decisions about how Bun is developed, and to use Claude Code.

delaminator3• 8 months ago

Deciding what to Implement

and

Implementing the Decisions

are complementary, one of these is being commoditised.

And, in fact, decimated.

Personally I am benefitting almost beyond measure because I can spend my time as the architect rather than the builder.

postalrat• 8 months ago

Because 90% is not 100%.

brobdingnagians3• 8 months ago

I'm curious what people think of quotes like these. Obviously it makes an explicit, falsifiable prediction. That prediction is false. There are so many reasons why someone could predict that it would be false. Is it just optimistic marketing speech, or do they really believe it themselves?

OkayPhysicist2• 8 months ago

Everybody knows that marketing speech is optimistic. Which means if you give realistic estimates, then people are going to assume those are also optimistic.

thesdev• 8 months ago

Why didn't they have the AI write a JS runtime instead of this acquisition?

delaminator3• 8 months ago

The big picture of “build a runtime” is an easier idea than “what would make this runtime better and how should the parts interact”.

somebodythere• 8 months ago

I think this wound up being close enough to true, it's just that it actually says less than what people assumed at the time.

It's basically the Jevons paradox for code. The price of lines of code (in human engineer-hours) has decreased a lot, so there is a bunch of code that is now economically justifiable which wouldn't have been written before. For example, I can prompt several ad-hoc benchmarking scripts in 1-2 minutes to troubleshoot an issue which might have taken 10-20 minutes each by myself, allowing me to investigate many performance angles. Not everything gets committed to source control.

Put another way, at least in my workflow and at my workplace, the volume of code has increased, and most of that increase comes from new code that would not have been written if not for AI, and a smaller portion is code that I would have written before AI but now let the AI write so I can focus on harder tasks. Of course, it's uneven penetration, AI helps more with tasks that are well-described in the training set (webapps, data science, Linux admin...) compared to e.g. issues arising from quirky internal architecture, Rust, etc.

howdyhowdy123• 8 months ago

That's ridiculous. Not it isn't even close.

rprend2• 8 months ago

Accurate for me. Accurate for basically every startup from the past 12 months. Prob not for legacy codebases, though.

jomohke3• 8 months ago

Why do people always stop this quote at the breath? The rest of it says that he still thinks they need tech employees.

.... and in 12 months, we might be in a world where the ai is writing essentially all of the code. But the programmer still needs to specify what are the conditions of what you're doing. What is the overall design decision. How we collaborate with other code that has been written. How do we have some common sense with whether this is a secure design or an insecure design. So as long as there are these small pieces that a programmer has to do, then I think human productivity will actually be enhanced

(He then said it would continue improving, but this was not in the 12 month prediction.)

Source interview: https://www.youtube.com/live/esCSpbDPJik?si=kYt9oSD5bZxNE-Mn

LauraMedia• 8 months ago

Given the horrible stability of Windows this year, it seems like Microsoft went all in on that

solumunus3• 8 months ago

It’s writing 90% of my code now but it’s 100% reliant on me to do that effectively.

tolerance2• 8 months ago

Shouts out to the fellow who half-broke the news in this submission that was presumably killed because of the aggressive paywall: https://news.ycombinator.com/item?id=46123627

And apparently the submission's source for being the only org I can tell that anticipated this: https://www.theinformation.com/articles/anthropic-advanced-t...

hedayet• 8 months ago

No strategic roadmap is ever going to tell you: "Build a $0-revenue JavaScript runtime and one day an AI company will acquire you"

supportengineer3• 8 months ago

Well, that was the playbook in the 1999-2001 dotcom days.

Windchaser• 8 months ago

Which is probably why no one's going to recommend it these days

...but hey, things are different during a bubble.

wmf3• 8 months ago

Honestly that's probably the best play. Monetizing dev tools directly is a nightmare.

reddalo2• 8 months ago

And you risk ending up like Postman or Insomnia, once beautiful software which is now widely hated by developers.

morkalork• 8 months ago

Countdown till Astral is acquired?

ironmagma• 8 months ago

It reminds me of hearing that music majors often do well in medical school. Want to go to medical school? Just major in music, duh.

OkayPhysicist2• 8 months ago

Ha, Physics majors get the same talk about law school. It's just the selection bias of selecting for people willing to make hard pivots filtering out the under-achieving, go-with-the-flow types.

westoque• 8 months ago

i really think this is part of the pitch deck for bun's funding. that a bigger company would acquire it for the technology. the only reason an AI company or any company for that matter would acquire it would be to:

1. acquire talent.

2. control the future roadmap of bun.

i think it's really 1.

mitchell_h• 8 months ago

I had the same thought when openai acquired rockset.

pizlonator• 8 months ago

Lots of strategists will tell you something like: "Build something that's useful and then there will be money".

That's 100% what happened to Bun. It's useful (like really useful) and now they're getting rewarded

klysm• 8 months ago

This wasn’t very high up on my list for acquisitions but props to the bun team for cashing in on the AI hype somehow!

tolerance2• 8 months ago

Who is expects Anthropic to migrate all their code to Codeberg.

_pdp_• 8 months ago

It makes total sense to me.

NiloCK• 8 months ago

This morning I found myself muttering something I won't repeat as a reaction to Claude Code's remarkably slow startup time.

Put the Bun folks directly on that please and nothing else.

supportengineer3• 8 months ago

Curious, how did he pay the bills when spending these years developing Bun?

skybrian5• 8 months ago

Bun was VC funded.

supportengineer3• 8 months ago

I thought it said he was building a voxel game in the browser?

krig5• 8 months ago

This announcement made me check in on the arbitrary code execution bug I reported that the Bun Claude bot created a PR for about 3 weeks ago:

https://github.com/oven-sh/bun/pull/24578

So far, someone from the bun team has left a bunch of comments like

Poor quality code

...and all the tests still seem to be failing. I looked through the code that the bot had generated and to me (who to be fair is not familiar with the bun codebase) it looks like total dogshit.

But hey, maybe it'll get there eventually. I don't envy "taylordotfish" and the other bot-herders working at Oven though, and I hope they get a nice payout as part of this sale.

bopbopbop77• 8 months ago

So you pushed a PR that breaks a bunch of tests, added a 5 layer nested if branch block that mixes concerns all over the place, then ignored the reviewer for three weeks, and you’re surprised they didn’t approve it?

throwaway2902• 8 months ago

So you pushed a PR that breaks a bunch of tests, added a 5 layer nested if branch block that mixes concerns all over the place, then ignored the reviewer for three weeks, and you’re surprised they didn’t approve it?

...Did you miss the part where Bun used Claude to generate that PR?:)

Master_Odin• 8 months ago

The OP directly says:

that the Bun Claude bot created a PR for about 3 weeks ago

The PR with bad code that's also been ignored was made by the bot that Bun made, and brags about in their acquisition post.

krig5• 8 months ago

I just reported the bug, it was the bot that was proudly mentioned in the announcement which created the PR and the code...

hprotagonist• 8 months ago

So, we can anticipate that the new Anthropic browser will now have the interpreter Ken Thompson previewed for us 41-odd years ago?

valbaca• 8 months ago

If Bun breaks, Claude Code breaks. Anthropic has direct incentive to keep Bun excellent.

and when this bubble pops down goes bun

sgt2• 8 months ago

Not really, we can just fork it?

ChrisbyMe2• 8 months ago

Interesting that this announcement is tied in with one for Claude Code revenue.

Feels like maybe AI companies are starting to feel the questions on their capital spending? They wanna show that this is a responsible acquisition.

TekMol2• 8 months ago

What is the business model behind open source projects like bun? How can a company "aquire" it and why does it do that?

In the article they write about the early days

    We raised a $7 million seed round

Why do investors invest into people who build something that they give away for free?

rglover3• 8 months ago

Either for a modest return when it sells or as a tax write off when it fails.

bcye4• 8 months ago

VCs do not invest for a modest return.

ChrisbyMe2• 8 months ago

I mean if you're getting X number of users per day and you don't need to pay for bandwidth or anything, there's gotta be SOME way to monetize down the line.

If your userbase or the current CEO likes it or not.

koakuma-chan2• 8 months ago

Ads. Have you seen the dotenv JavaScript package?

taylorlapeyre• 8 months ago

The post mentions why - Bun eventually wanted to provide some sort of cloud-hosting saas product.

TekMol2• 8 months ago

Everyone could offer a cloud-hosted saas product that involves bun, right?

Why invest into a company that has the additional burden of developing bun, why not in a company that does only the hosting?

knowitnone3• 8 months ago

Except Amazon would beat them to it

Supercompressor• 8 months ago

Free now isn't free forever. If something has inherent value then folks will be willing to pay for it.

aizk4• 8 months ago

Well, if they suddenly changed the license, we'd get a new Redis --> Valkey situation. Or even more recently, look at minio no longer maintaining their core open source project!

catapart2• 8 months ago

oh well. it was cool while it lasted! I guess I'll figure out how to make deno do what I want, now.

reactordev6• 8 months ago

Bun is such a great runtime. If you haven't tried it, try it. It's got bells and whistles.

This will make sure Bun is around for many, many, years to come. Thanks Anthropic.

Why Bun?

Easy to setup and go. bun run <something.ts>

Bells and whistles. (SQL, Router, SPA, JSX, Bundling, Binaries, Streams, Sockets, S3)

Typescript Supported. (No need to tsc, bun can transpile for you)

Binary builds. (single executables for easy deployment)

Full Node.js Support. (The whole API)

Full NPM Support. (All the packages)

Native modules. (90% and getting better thanks to Zig's interop)

S3 File / SQL Builtin. (Blazingly Fast!)

You should try it. Yes, others do these things too, but we're talking about Bun.

dawnerd• 8 months ago

This will make sure Bun is around for many, many, years to come.

Well, until the bubble bursts and Anthropic fizzles out or gets acquired themselves.

reddalo2• 8 months ago

...and then it's going to be time for an "incredible journey" post.

holysoles• 8 months ago

If they keep it MIT licensed, if/when things come crashing down, I think its reasonable to think Bun would continue on in some form, even if development slows pace without paid contributors.

croes3• 8 months ago

Does it have permission flags yet like deno has?

johncolanduoni6• 8 months ago

I’ve never understood the security utility of the Deno flags. What practical attack would they protect you from? Supply chain seems to be the idea, but how many npm packages do people use that neither:

* Get run by devs with filesystem permissions

* Get bundled into production

mtoner23• 8 months ago

It'll be around until they realize it makes 0$, and costs them millions per year in salaries/stock. then it will quietly die

oheyadam• 8 months ago

You think they wouldn't have done that napkin math before deciding to acquire it?

reactordev6• 8 months ago

Anthropic uses a lot of bun. In fact, they bet the farm on it.

tpetry• 8 months ago

Its not 100% nodejs compatible. I see enough non-green dots in their own official report https://bun.com/docs/runtime/nodejs-compat

And even in packages with full support you can find many github issues that bun behaves directly which leads to some bugs.

reactordev6• 8 months ago

Not saying it’s 100%, there’s still the repl missing but all of node’s API is available in the sense that it’s ABI compatible (or will be very near term).

everlier• 8 months ago

So many comments about reasoning here, yet none about the very obvious one, it's not stability of the infrastructure, it's future direction of a product like Claude Code. They need to know how to continue their optimisation machine to fit developers needs the best way possible (for good or for worse).

I guess we should wait for some opt-out telemetry some time soon. It'll be nothing too crazy at first, but we'll see how hungry they are for the data.

sulam2• 8 months ago

Don't they already have a ton of telemetry from Claude Code itself? I'd be shocked and expect an instant fork if Anthropic telemetry was added to Bun.

egorfine• 8 months ago

Well, Bun is MIT-licensed. So once they change the license and/or kill the project, the community can fork it easily.

wmf3• 8 months ago

The point of this deal is that they do not need to change the license. Nobody will ever pay for Bun and now they don't have to force it.

egl2020• 8 months ago

Can anyone provide some color around this: "I started porting esbuild's JSX & TypeScript transpiler from Go to Zig"? Hypothetical benefits include monolanguage for development, better interoperability with C and C++, no garbage collection, and better performance. What turned out to be realized and relevant here? Please, no speculation or language flames or wars.

ryanvogel• 8 months ago

video covering it

https://www.youtube.com/watch?v=6hEiUq8jWIg

lkqjweflkj• 8 months ago

Not to be confused with Bunn [1], the coffee maker makers.

[1] www.bunn.com

clot27• 8 months ago

deno won, rust won

joewhale• 8 months ago

why couldn't Anthropic simply use Claude Code to write Bun over the weekend??

Thrymr• 8 months ago

It is open source (MIT license), Claude should have a pretty good start on it already.

jaredcwhite• 8 months ago

My long-term bet on Node being "boring" and "stable" continues to pay major dividends. So glad I never invested any time and effort on this ecosystem…

pjmlp11• 8 months ago

That is the way, when one is long time around, there are these alternatives coming and going, while the reference platforms keep going.

fud1012• 8 months ago

must be nice to have a 1gb node_modules folder for hello world

kelvinjps102• 8 months ago

on the post they try to reassure the following question "If I bet my work project or company's tech stack on Bun, will it still be around in five or ten years?" and the thing is that we don't know if Anthropic itself will be around 5 to ten years

threecheese• 8 months ago

Interesting. Looking through a strategic lens, I feel like this is related to the $1,000 free credit for Claude Code Web (I used a few hundred). What the heck are they aiming for? CodeAct? (https://arxiv.org/abs/2402.01030)

zecheng• 8 months ago

So Anthropic sees its CLI (in TypeScript) as the first-class product and maybe planning to expand the claude code with more JS based agents / ecosystem? Especially owning the runtime gives a lot of control over developer experience.

forrestthewoods2• 8 months ago

Why the hell is a CLI coding agent built in JavaScript?

It’s wild what happens when a generation of programmers doesn’t know anything except webdev. How far from grace we have fallen.

simonw28• 8 months ago

The big advantage of a language like JavaScript of Python for a CLI tool of this nature is that they naturally support adding extensions or plugins.

That's quite a bit harder if your tool is built using a compiled language like Go.

forrestthewoods2• 8 months ago

Ehhhh. In either case you have to define a neat clean plugin API. Whether it loads a DLL/SO or just some scripts isn’t that huge of a difference.

gethly• 8 months ago

I started porting esbuild's JSX & TypeScript transpiler from Go to Zig

How was Go involved there before Zig?

simonw28• 8 months ago

esbuild is still a Go app today: https://github.com/evanw/esbuild

The first hints of what become Bun were when Jared experimented at porting that to Zig.

hinkley5• 8 months ago

I wonder if this is a sign of AI companies trying to pivot?

Bun will ship faster.

That'll last until FY 2027. This is an old lie that acquirers encourage the old owner to say because they have no power to enforce it, and they didn't actually say it so they're not on the hook. It's practically a cheesy pickup line, and given the context, it kinda is.

matrixhelix• 8 months ago

This is why we can't have nice things

hinkley5• 8 months ago

I would like to clarify that I wish I weren't right but I probably am.

unsungNovelty3• 8 months ago

"Insanity Is Doing the Same Thing Over and Over Again and Expecting Different Results"

fnands• 8 months ago

On your first point: It doesn't read like that to me. It seems like they built one of their key products (Claude Code) on top of Bun, and want to have a say in it's development.

CuriouslyC• 8 months ago

I'm sure the Bun team will get Claude Code straightened out. Weird acquisition, but TBH Anthropic needed to fill this hole.

Jarred4• 8 months ago

I work on Bun.

Happy to answer any questions

linkage2• 8 months ago

You said elsewhere that there were many suitors. What is the single most important thing about Anthropic that leads you to believe they will be dominant in the coming years?

convenwis• 8 months ago

No idea about his feelings but believing that they will be dominant wouldn't have to be the reason he chose them. I could easily imagine that someone would decide based on (1) they offered enough money and (2) values alignment.

elktown3• 8 months ago

Is this acquihiring?

simonw28• 8 months ago

No. Anthropic need Bun to be healthy because they use it for Claude Code.

alexandre_m• 8 months ago

I consider this more of a strategic acquisition.

Skywalker132• 8 months ago

Hi Jarred,

I contributed to Bun one time for SQLite. I've a question about the licensing. Will each contributor continue to retain their copyright, or will a CLA be introduced?

Thanks

jasnell2• 8 months ago

With Bun's existing OSS license and contribution model, all contributors retain their copyright and Bun retains the license to use those contributions. An acquisition of this kind cannot change the terms under which prior contributions were made without explicit agreement from all contributors. If Bun did switch to a CLA in the future, just like with any OSS project, that would only impact future contributions made after that CLA went into effect and it depends entirely on the terms established in that hypothetical CLA.

jannes• 8 months ago

Congrats on the payday :)

Do you think Anthropic might request you implement private APIs?

kyyol• 8 months ago

This is an interesting question; not to be too naive, but are there examples in the wild about this scenario? First I’ve heard of private APIs for something open source like this and my interest is piqued!

linkage2• 8 months ago

How much of your day-to-day is spent contributing code to the Bun codebase and do you expect it to decrease as Anthropic assigns more people to work on Bun?

msuniverse2026• 8 months ago

Any thoughts on the claude "soul document" that was leaked this week?

genshii• 8 months ago

Hi Jarred, thanks for all your work on Bun.

I know that one thing you guys are working on or are at least aware of is the size of single-file executables. From a technical perspective, is there a path forward on this?

I'm not familiar with Bun's internals, but in order to get the size down, it seems like you'd have to somehow split up/modularize Bun itself and potentially JavaScriptCore as well (not sure how big the latter is). That way only the things that are actually being used by the bundled code are included in the executable.

Is this even possible? Is the difficulty on the Bun/Zig side of things, or JSC, or something else? Seems like a very interesting (and very difficult) technical problem.

fishmicrowaver4• 8 months ago

Yeah why are you not out on a boat somewhere enjoying this moment? Go have fun please.

almosthere2• 8 months ago

Acq's typically have additional stips you have to follow - they probably have new deadlines and some temporary stress for the next few months.

brrrrrm• 8 months ago

on Bun's website, the runtime section features HTTP, networking, storage -- all are very web-focused. any plans to start expanding into native ML support? (e.g. GPUs, RDMA-type networking, cluster management, NFS)

Jarred4• 8 months ago

Probably not. When we add new APIs in Bun, we generally base the interface off of popular existing packages. The bar is very high for a runtime to include libraries because the expectation is to support those APIs ~forever. And I can’t think of popular existing JS libraries for these things.

atonse• 8 months ago

One more thing I hope doesn't change, is the fun Release videos :-) I really enjoy them. They're very apple-y, and for just a programming tool.

losvedir3• 8 months ago

I'm sort of surprised to see that you used Claude Code so much. I had a vague idea that "Zig people" were generally "Software You Can Love" or "Handmade Software Movement" types, about small programs, exquisitely hand-written, etc, etc. And I know Bun started with an extreme attention to detail around performance.

I would have thought LLM-generated code would run a bit counter to both of those. I had sort of carved the world into "vibe coders" who care about the eventual product but don't care so much about the "craft" of code, and people who get joy out of the actual process of coding and designing beautiful abstractions and data structures and all that, which I didn't really think worked with LLM code.

But I guess not, and this definitely causes me to update my understanding of what LLM-generated code can look like (in my day to day, I mostly see what I would consider as not very good code when it comes from an LLM).

Would you say your usage of Claude Code was more "around the edges", doing things like writing tests and documentation and such? Or did it actually help in real, crunchy problems in the depths of low level Zig code?

vector_spaces• 8 months ago

I am not your target with this question (I don't write Zig) but there is a spectrum of LLM usage for coding. It is possible to use LLMs extensively but almost never ship LLM generated code, except for tiny trivial functions. One can use them for ideation, quick research, or prototypes/starting places, and then build on that. That is how I use them, anyway

Culturally I see pure vibe coders as intersecting more with entrepreneurfluencer types who are non-technical but trying to extend their capabilities. Most technical folks I know are fairly disillusioned with pure vibe coding, but that's my corner of the world, YMMV

abnercoimbre2• 8 months ago

Handmade Cities founder here.

We never associated with Bun other than extending an invitation to rent a job booth at a conference: this was years ago when I had a Twitter account, so it's fair if Jarred doesn't remember.

If Handmade Cities had the opportunity to collaborate with Bun today, we would not take it, even prior to this acquisition. HMC wants to level up systems while remaining performant, snappy and buttery smooth. Notable examples include File Pilot [0] or my own Terminal Click (still early days) [1], both coming from bootstrapped indie devs.

I'll finish with a quote from a blog post [2]:

Serious Handmade projects, like my own Terminal Click, don’t gain from AI. It does help at the margins: I’ve delegated website work since last year, and I enjoy seamless CI/CD for my builds. This is meaningful. However, it fails at novel problems and isn’t practical for my systems programming work.

All that said, I congratulate Bun even as we disagree on philosophy. I imagine it's no small feat getting acquired!

[0] https://filepilot.tech

[1] https://terminal.click

[2] https://handmadecities.com/news/summer-update-2025/

Aurornis2• 8 months ago

I had a vague idea that "Zig people" were generally "Software You Can Love" or "Handmade Software Movement" types, about small programs, exquisitely hand-written, etc, etc.

In my experience, the extreme anti-LLM people and extreme pro-vibecoding people are a vocal online minority.

If you get away from the internet yelling match, the typical use case for LLMs is in the middle. Experienced developers use them for some small tasks and also write their own code. They know when to switch between modes and how to make the most of LLMs without deferring completely to their output.

Most of all: They don't go around yelling about their LLM use (or anti-use) because they're not interesting in the online LLM wars. They just want to build things with the tools available.

LexiMax• 8 months ago

I had a vague idea that "Zig people" were generally "Software You Can Love" or "Handmade Software Movement" types, about small programs, exquisitely hand-written, etc, etc.

I feel like an important step for a language is when people outside of the mainline language culture start using it in anger. In that respect, Zig has very much "made it."

That said, if I were to put on my cynical hat, I do wonder how much of that Anthropic money will be donated to the Zig Software Foundation itself. After all, throwing money at maintaining and promoting the language that powers a critical part of their infrastructure seems like a mutually beneficial arrangement.

weird-eye-issue• 8 months ago

"exquisitely hand-written"

This sounds so cringe. We are talking about computer code here lol

dgroshev2• 8 months ago

I'm not sure about exquisite and small.

Bun genuinely made me doubt my understanding of what good software engineering is. Just take a look at their code, here are a few examples:

- this hand-rolled JS parser of 24k dense, memory-unsafe lines: https://github.com/oven-sh/bun/blob/c42539b0bf5c067e3d085646... (this is a version from quite a while ago to exclude LLM impact)

- hand-rolled re-implementation of S3 directory listing that includes "parsing" XML via hard-coded substrings https://github.com/oven-sh/bun/blob/main/src/s3/list_objects...

- MIME parsing https://github.com/oven-sh/bun/blob/main/src/http/MimeType.z...

It goes completely contrary to a lot of what I think is good software engineering. There is very little reuse, everything is ad-hoc, NIH-heavy, verbose, seemingly fragile (there's a lot of memory manipulation interwoven with business logic!), with relatively few tests or assurances.

And yet it works on many levels: as a piece of software, as a project, as a business. Therefore, how can it be anything but good engineering? It fulfils its purpose.

I can also see why it's a very good fit for LLM-heavy workflows.

dgellow2• 8 months ago

I love zig, in my experience claude code is extremely good with the language if you invest lots of time on design sessions, to the point where I spend >90% of my time only discussing design with claude. The fact it has easy access to sources of the whole stdlib by just downloading the zig tarball makes it really simple to have a feedback loop where it implement most of the boilerplate on its own. The quality of AI code is really something that can be well controlled with clear guidelines, strict reviews, comprehensive design sessions, and a great test infrastructure

thatSteveFan• 8 months ago

I interviewed for the Bun guys and totally flopped because I was not prepared for the interview format. It was "here's a task, do whatever you need to including AI to get it done". From that, I'd infer that the usage is pretty substantial.

sktrdie• 8 months ago

I've never personally used Bun. I use node.js I guess. What makes Bun fundamentally better at AI than, say, bundling a node.js app that can run anywhere?

If the answer is performance, how does Bun achieve things quicker than Node?

postepowanieadm• 8 months ago

Easier deployment, you may generate a single binary.

420official• 8 months ago

Does this acquisition preclude implementing an s3 style integration for AWS bedrock? Also is IMDSv2 auth on the roadmap?

rikafurude21• 8 months ago

Any chance there will be some kind of updating mechanism for 'compiled' bun executables?

Jarred4• 8 months ago

I have a PR that’s been sitting for awhile that exposes the extra options from the renameat2 and renameatx_np syscalls which is a good way to implement self-updaters that work even when multiple processes are updating the same path on disk at the same time. These syscalls are supported on Linux & macOS but I don’t think there’s an equivalent on Windows. We use these syscalls internally for `bun install` to make adding packages into the global install cache work when multiple `bun install` processes are running simultaneously

No high-level self updater api is planned right now, but yes for at least the low level parts needed to make a good one

asdfwaafsfw• 8 months ago

"work on Bun." LOL.

Congratulations.

stack_framer3• 8 months ago

Are you at liberty to divulge how much Anthropic paid for Bun?

urbandw311er• 8 months ago

Hi Jarred. Congratulations on the acquisition! Did (or will) your investors make any profit on what they put into Bun?

tovazm• 8 months ago

Thanks, Jarred. Seeing what you built with Bun has been a real inspiration, the way one focused engineer can shift an entire ecosystem. It pushed me back into caring about the lower-level side of things again, and I’m grateful for that spark. Congrats on the acquisition, and excited to see what’s next

franciscop• 8 months ago

Amazing news, congrats! Been using Bun for a long while now and I love it.

Is there anything I could do to improve this PR/get a review? I understand you are def very busy right now with the acquisition, but wanted to give my PR the best shot:

https://github.com/oven-sh/bun/pull/24514

djdjsjejb• 8 months ago

how the helldid you got that og name here in hn

asking the real questions

jrflowers• 8 months ago

What happens to Bun in a scenario where Anthropic goes under?

hungryhobbit2• 8 months ago

Why can't you make CLI autocompletions work? It's so basic, but the ticket has languished for almost as long as bun has existed!

Aeolun8• 8 months ago

Because nobody (including you, apparently) cares enough to implement it?

Sincere6066• 8 months ago

how can you sleep at night?

gaws4• 8 months ago

The money was too good to pass up.

cdelsolar• 8 months ago

my wife and i call each other bun all the time, and it's really weird to see an article full of Buns

baxuz2• 8 months ago

What are your thoughts on using AI generated cartoons as your primary marketing material on social media? For instance https://xcancel.com/bunjavascript/status/1955893818529866055...

PurpleRamen3• 8 months ago

What happened to the voxel game that kickstarted the idea of bun? Was it ever finished? How much did it benefit from bun?

gaws4• 8 months ago

Are contributors getting cash or Anthropic equity as part of the acquisition?

baby3• 8 months ago

I love Bun and use it daily, but I'm still very frustrated by all the configuration that one needs ATM when working in the js ecosystem. Do you guys see yourself integrating more and more, and moving more and more towards a "convention over configuration", to bring a more streamlined dev experience (that languages like Golang and Rust have, for example)

kristianp3• 8 months ago

I'm confused. I installed claude code with:

    npm install -g @anthropic-ai/claude-code

I thought claude code just used Nodejs? I didn't realise the recommended install used a different runtime.

simonw28• 8 months ago

They switched to recommending this as the installation method back in July:

  curl -fsSL https://claude.ai/install.sh | bash

That install script gives you a single binary which is created using Bun.

kristianp3• 8 months ago

Maybe that's why I didn't have some bugs people were reporting on HN, or because I was using linux.

elktown3• 8 months ago

I've seen a few of these seemingly random acquisitions lately, and I congratulate the companies and individuals that are acquired during this gold rush, but it definitely feels awkwardly artificial.

ChrisGreenHeur• 8 months ago

A single bun? Is that really newsworthy?

saint_yossarian• 8 months ago

Oh you silly goose.

stack_framer3• 8 months ago

Anyone know how much Anthropic paid for Bun? I assume it was at least $26M, so Bun could break even and pay back its own investors, but I didn't see a number in the announcements from Anthropic or Bun.

mudkipdev• 8 months ago

Claude said $187M

intrepidsoldier• 8 months ago

In other news - Amp Code is a separate company now - https://ampcode.com/news/amp-inc

bovermyer• 8 months ago

When I saw the headline I was ready to be mad, but after reading the post, I'm cautiously on board with this.

bblaylock2• 8 months ago

This reads more like Anthropic wanted to hire Jarred and Jarred wants to work with AI rather than build a Saas product around bun. I doubt it has anything to do with what is best for bun the project. Considering bun always seemed to value performance more than all else, the only real way for them to continue pursuing that value would be to move into the actual js engine design. This seems like a good pivot for Jarred personally and likely a loss for bun.

thatoneengineer• 8 months ago

Nah, it reads like the normal logic behind the consulting model for open source monetization, except that Bun was able to make it work with just one customer. Good for them, though it comes with some risks, especially when structured as an acquisition.

simonw28• 8 months ago

It doesn't read like that to me at all. This reads to me like Anthropic realizing that they have $1bn in annual revenue from Claude Code that's dependent on Bun, and acquiring Bun is a great and comparatively cheap way to remove any risk from that dependency.

Karrot_Kream4• 8 months ago

I'm also curious if Anthropic was worried about the funding situation for Bun. The easiest way to allay any concerns about longevity is to just acquire them outright.

_jab• 8 months ago

This argument doesn’t make much sense to me. Claude Code, like any product, presumably has dozens of external dependencies. What’s so special about Bun specifically that motivated an acquisition?

bblaylock2• 8 months ago

I haven't had any issue moving projects between node, bun, and deno for years. I don't agree that the risk of bun failing as a company affects anthropic at all. Bun has a permissible license that anthropic could fork from, anthropic likely knew that oven had a long runway and isn't in immediate danger, and switching to a new js cli tool is not the huge lift most people think it is in 2025. Why pay for something you are already getting for free and can expect to keep getting for free for at least four years, and buy for less if it fails later?

manojlds• 8 months ago

Really? What risk is even there?

rco8786• 8 months ago

Except bun is OSS, so they could have just forked if something happened

dts• 8 months ago

A lot of people seem confused about this acquisition because they think of Bun as a node.js compatible bundler / runtime and just compare it to Deno / npm. But I think its a really smart move if you think of where Bun has been pushing into lately which is a kind of cloud-native self contained runtime (S3 API, SQL, streaming, etc). For an agent like Claude Code this trajectory is really interesting as you are creating a runtime where your agent can work inside of cloud services as fluently as it currently does with a local filesystem. Claude will be able to leverage these capabilities to extend its reach across the cloud and add more value in enterprise use cases

robertjpayne2• 8 months ago

This is an insanely good take I never thought of.

hoppp2• 8 months ago

It's fine but why is Js a good language for agents? I mean sure its faster than python but wouldn't something that compiles to native be much better?

chatmasta• 8 months ago

JS has the fastest, most robust and widely deployed sandboxing engines (V8, followed closely by JavaScriptCore which is what Bun uses). It also has TypeScript which pairs well with agentic coding loops, and compiles to the aforementioned JavaScript which can run pretty much anywhere.

AstroBen2• 8 months ago

It's widespread and good enough. The language just doesn't matter that much in most cases

aizk4• 8 months ago

TS is enormous, has endless training data, and can interact with virtually anything on the Internet these days. Also, strong typing is very very useful for AI coding context.

ramoz3• 8 months ago

The answer is typescript is a much simpler and more pleasant developer experience than any other language. These are products they need to, and often originate from, fast churn of code/features.

Otherwise they’d be building these types of things in Rust.

ants_everywhere• 8 months ago

The writeup makes it sound like an acquihire, especially the "what changes" part.

ChatGPT is feeling the pressure of Gemini [0]. So it's a bit strange for Anthropic to be focusing hard on its javascript game. Perhaps they see that as part of their advantage right now.

[0] https://timesofindia.indiatimes.com/technology/tech-news/goo...

jorblumesea• 8 months ago

That's a really cool use case and seems super helpful. working cloud native is a chore sometimes. having to fiddle with internal apis, acl/permissions issues.

davnicwil• 8 months ago

Isn't what you're describing just a set of APIs with native bindings that the LLM can call?

I'm not sure I understand why it's necessary to even couple this to a runtime, let alone own the runtime?

Can't you just do it as a library and train/instruct the LLM to prefer using that library?

ignoramous6• 8 months ago

Mostly, just Jarred Sumner makes it worth it for Anthropic.

btown• 8 months ago

Yea - if you want a paranoidly-sandboxed, instant-start, high-concurrency environment, not just on beefy servers but on resource-constrained/client devices as well, you need experts in V8 integration shenanigans.

Cloudflare Workers had Kenton Varda, who had been looking at lightweight serverless architecture at Sandstorm years ago. Anthropic needs this too, for all the reasons above. Makes all the sense in the world.

gorjusborg• 8 months ago

Bun isn't based on V8, it's JavaScriptCore, but your point still stands.

orliesaurus2• 8 months ago

you left out the best part...what happened to Kenton? He looked at lightweight serverless architecture..and then what?

littlestymaar2• 8 months ago

Yea - if you want a paranoidly-sandboxed, instant-start, high-concurrency environment, not just on beefy servers but on resource-constrained/client devices as well, you need experts in V8 integration shenanigans.

To be honest, that sounds more like a pitch for deno than for bun, especially the “paranoidly sandboxed” part.

milowata• 8 months ago

Could also be a way to expand the customer for Claude Code from coding assistant to vibe coding, a la Replit creating a hosted app. CC working more closely with Bun could make all that happen much faster:

Our default answer was always some version of "we'll eventually build a cloud hosting product.", vertically integrated with Bun’s runtime & bundler.

ok_dad3• 8 months ago

Yea, they just posted this a few days ago:

https://www.anthropic.com/engineering/advanced-tool-use

They discussed how running generated code is better for context management in many cases. The AI can generate code to retrieve, process, and filter the data it needs rather than doing it in-context, thus reducing context needs. Furthermore, if you can run the code right next to the server where the data is, it's all that much faster.

I see Bun like a Skynet: if it can run anywhere, the AI can run anywhere.

yellow_lead2• 8 months ago

Java can run anywhere too

cyanydeez• 8 months ago

Jesus wept, for the nerds joyfully want skyney

VerifiedReports5• 8 months ago

What do you mean by "context" here?

gz5• 8 months ago

Claude will be able to leverage these capabilities to extend its reach across the cloud and add more value in enterprise use cases

100%. even more robust if paired with an overlay network which provides identity based s3 access (rather than ip address/network based). else server may not have access to s3/cloud resource, at least for many enterprises with s3 behind vpn/direct connect.

ditto for cases when want agent/client side to hit s3 directly, bypassing the server, and agent/client may not have permitted IP in FW ACL, or be on vpn/wan.

1vuio0pswjnm72• 8 months ago

As a commandline end user who prefers to retreive data from the www as text-only, I see deno and bun as potential replacements (for me, not necessarily for anyone else) for the so-called "modern" browser in those rare cases where I need to interpret Javascript^1

At present the browser monstrosity is used to (automatically, indiscriminantly) download into memory and run Javascripts from around the web. At least with a commandline web-capable JS runtime monstrosity the user could in theory exercise more control over what scripts are downloaded and if and when to run them. Perhaps more user control over permissions to access system resources as well (cf. corporate control)

1. One can already see an approach something like this being used in the case of

https://github.com/yt-dlp/yt-dlp/wiki/EJS

where a commandline JS runtime is used without the need for any graphics layer (advertising display layer)

tclancy• 8 months ago

Is this something I’d have to own a tv to understand?

1vuio0pswjnm72• 8 months ago

Why do Apple, Microsoft, Google, Meta, OpenAI, AWS and other so-called "tech" companies advertise on TV

What about people who do not own a TV

jillesvangurp• 8 months ago

I'm not confused about the acquisition but about the investment. What were the investors thinking? This is an open source development tool with (to date), 0$ of revenue and not even the beginnings of a plan for getting such a thing.

The acquisition makes more sense. A few observations:

- no acquisition amount was announced. That indicates some kind of share swap where the investors change shares for one company into another. Presumably the founder now has some shares in Anthropic and a nice salary and vesting structure that will keep him on board for a while.

- The main investor was Kleiner Perkins. They are also an investor in Anthropic. 100M in the last round, apparently.

Everything else is a loosely buzzword compatible thingy for Anthropic's AI coding thingy and some fresh talent for their team. All good. But it's beside the point. This was an investor bailout. They put in quite a bit of money in Bun with exactly 0 remaining chance of that turning into the next unicorn. Whatever flaky plan there once might have been for revenue that caused them to invest, clearly wasn't happening. So, they liquidated their investment through an acquihire via one of their other investments.

Kind of shocking how easy it was to raise that kind of money with essentially no plan whatsoever for revenue. Where I live (Berlin), you get laughed away by investors (in a quite smug way typically) unless you have a solid plan for making them money. This wouldn't survive initial contact with due diligence. Apparently money still grows on trees in Silicon Valley.

I like Bun and have used it but from where I'm sitting there was no unicorn lurking there, ever.

djfdat• 8 months ago

They don't need Bun to make revenue, but they need Bun to continue existing and growing for their products to make revenue. Now they can ensure its survival, push for growth, and provide resources so that Bun can build the best product rather than focus on making money.

danenania3• 8 months ago

Investors are really bad at predicting up front what can become a unicorn and what can’t.

wrathofmonads3• 8 months ago

Java was doing "cloud-native, stripped down (jlink) image, self-contained runtime with batteries included" long before Bun existed. There's also GraalVM for one executable binary if one's ambitious.

kopirgan• 8 months ago

I'm also confused.. Why does a generic AI company that helps coding as one of main offering get deeply in bed with one tech stack

I mean would it have made sense to acquire golang if it were on sale?

qwm• 8 months ago

They want to make sure the runtime they depend on continues to be maintained. It's still niche and new, so its continued existence isn't as sure as something like Go.

catigula2• 8 months ago

I don't get the whole 'cloud' thing for AI agents. It feels forced. Who is actually using these services?

danenania3• 8 months ago

Non-developers usually prefer them to IDE or terminal based tools.

baby3• 8 months ago

if I would guess Anthropic is (rightly) frustrated with the state of the js ecosystem and is taking the best attempt so far to make the js experience much more streamlined for their developers. Convention over configuration might finally be coming to the js ecosystem?

Sirikon• 8 months ago

Hahahahahhaahhahahahahahhahahahahahhahahaha.

Regards.

patrick4urcloud• 8 months ago

wow !

Anonyneko• 8 months ago

I'm only surprised that it wasn't Vercel who bought them.

pier254• 8 months ago

I wonder what this means for Deno.

Will this make it more or less likely for people to use Bun vs Deno?

And now that Bun doesn't need to run a profitable cloud company will they move faster and get ahead of Deno?

GianFabien2• 8 months ago

I think Deno's management have been somewhat distracted by their ongoing lawsuits with Oracle over the release of the Javascript trademark.

I started out with Deno and when I discovered Bun, I pivoted. Personally I don't need the NodeJS/NPM compatability. Wish there was a Bun-lite which was freed of the backward compatability.

pier254• 8 months ago

I'm in a similar position.

I use Hono, Zod, and Drizzle which AFAIK don't need Node compat.

IIRC I've only used Node compat once to delete a folder recursively with rm.

Zambyte2• 8 months ago

What do you dislike about having node compatibility?

carefulfungi• 8 months ago

Ironically, this was early Deno - but then adoption required backwards compatibility.

pjmlp11• 8 months ago

In regards to Deno, to me that means their business is not really flying and they need this kind of distractions instead.

Amount of people at big corps that care about their lawsuit, and would switch their IT guidelines from node to Deno due to such heroic efforts?

Zero.

spartanatreyu2• 8 months ago

Will this make it more or less likely for people to use Bun vs Deno?

I'm not sure it will make much of a difference in the short term.

For those who were drawn to Bun by hype and/or some concerns around speed, they will continue to use Bun.

For me personally, I will continue to use Node for legacy projects and will continue using Deno for current projects.

I'm not interested in Bun for it's hype (since hype is fleeting). I have a reserved interested in Bun's approach to speed but I don't see it being a significant factor since most JS speed concerns come from downloading dependencies (which is a once-off operation) and terrible JS framework practices (which aren't resolved by changing engines anyway).

----------------------------

The two largest problems I see in JS are:

1. Terrible security practices

2. A lack of a standard library which pushes people into dependency hell

Deno fixes both of those problems with a proper permission model and a standard library.

----------------------------

And now that Bun doesn't need to run a profitable cloud company will they move faster and get ahead of Deno?

I think any predictions between 1-10 years are going to be a little too chaotic. It all depends on how the AI bubble goes away.

But after 10 years, I can see runtimes switching from their current engines to one based on Boa, Kiesel or something similar.

pier254• 8 months ago

Deno fixes both of those problems with a proper permission model and a standard library

Bun has a better standard library than Deno. You get a DB driver, S3 client, etc which on Deno are all third party deps. It was the main reason I got interested in Bun. The speed is nice though during dev. Everything feels instant.

sergiotapia• 8 months ago

Prediction Bun is absorbed in house and used by Anthropic to have faster/cheaper places for Claude to run code.

It fades away as a direct to developer tool.

This is a good thing for Deno.

notnullorvoid4• 8 months ago

Bun and Deno's goals seem quite different, I don't expect that to change. Bun is a one stop shop with an ever increasing number of built-in high-level APIs. Deno is focused on low level APIs, security, and building out a standard lib/ecosystem that (mostly) supports all JS environments.

People who like Bun for what it is are probably still going to, and same goes for Deno.

That being said I don't see how Anthropic is really adding long term stability to Bun.

joshcsimmons• 8 months ago

Deno is dead. Seems like there haven't been very relevant or user-informed changes on their roadmap for year(s) now.

ignoramous6• 8 months ago

Deno is dead.

Not yet; similar concerns were addressed by Dahl 6mo ago: https://deno.com/blog/greatly-exaggerated / https://archive.vn/L6His

huqedato• 8 months ago

Aham, tx. Good to know - I'll switch my projects to Deno.

killingtime74• 8 months ago

you know Deno is VC backed right

ngrilly2• 8 months ago

Considering that 1) Bun is written in Zig, 2) Zig has a strict no-AI policy [1], and 3) Bun has joined Claude, it seems that Bun and Zig are increasingly culturally apart.

[1] https://ziglang.org/code-of-conduct/#strict-no-llm-no-ai-pol...

M4v3R• 8 months ago

Nothing I found says anything about Zig folks being inherently against AI. It just looks like they don’t want to deal with “AI Slop” in contributions to their project, which is very understandable.

ignoramous6• 8 months ago

Bun and Zig are increasingly culturally apart

That's like saying GCC and NodeJS are culturally apart, as if that has significant bearing on either?

dan-robertson• 8 months ago

You’re reading a code of conduct for contributing to the zig project. I don’t think everything there is guidance for everything written in zig, eg ‘English is encouraged’ is something one might not want for a project written in zig by native French-speakers, and I don’t think that’s something zig would want to suggest to them. I read the AI part is much more motivated by the asymmetries of open source project contribution than any statement about the language itself. Fly-by AI contributions are bad because they make particularly poor use of maintainer time. Similar to the rule on proposing language changes, which can suck up lots of reading/thinking/discussion time. When you have people regularly working together (eg those people in anthropic working on bun) the incentives are different because there is a higher cost to wasting your colleague’s time.

bibimsz• 8 months ago

bullish for js, bearish for python?

indigodaddy• 8 months ago

Has CC always used Bun? When it tries it out many months ago it was an npm install not bun install in their instructions (although I did use bun install myself). Just odd that if they were using bun, why the installation wasn’t specifically a “bun install” (I suppose they were trying to keep it vanilla for the npm masses?)

djfobbz• 8 months ago

I finally hope Bun will start to support and work on WSL1

bilekas• 8 months ago

Genuine question, why acquisition when anthropic could simply sponsor, contribute and influence instead?

Acquisition seems like a large overhead and maybe a slight pivot to me.

piskov2• 8 months ago

Genuine question: why js?

Why not something like c#: native, fast, crossplatform, strongly-typed, great tooling, supports both scripting (ie single file-based) and compiled to a binary with no dependency whatsoever (nativeAOT), great errors and error stacks, list goes on.

All great for AI to recover during its iterations of generating something useful.

Genuinely perplexed.

hoppp2• 8 months ago

Because js became an everything language that everyone can write and its the only language you ever need.

I dislike it also..

awesome_dude2• 8 months ago

You could make a better argument for Go (compiles to native for multiple targets, zero actual dependencies (no need for a platform or virtual machine on the target)

piskov2• 8 months ago

C# no longer requires .net installed or bundled inside exe.

Like I’ve said: NativeAOT

https://learn.microsoft.com/en-us/dotnet/core/deploying/nati...

mrcsharp4• 8 months ago

C# has AOT compilation producing native, single file assemblies. A bit behind on this compared to Go, but it's there.

morshu90015• 8 months ago

Go is the most portable compiled language out there and makes a lot of compromises with the interpreted lang world. But it's got its own issues.

metaltyphoon• 8 months ago

zero actual dependencies

on Linux only with CGO_ENABLED=0 and good luck using some non web related 3rd party module which can be used with CGO disabled.

mrcsharp4• 8 months ago

Sadly, this will be the trend with things moving forward. JS is perceived as a good language and LLMs are meant to make them even easier to write. It is not about the mertis of a language. It's about which languages LLMs are "good" at.

hexasquid• 8 months ago

If I was to pick a language, I'd pick the one all developers agree is the best.

nixosbestos• 8 months ago

Ahahahahhahahahahhahahahaahaha. Please tell me this is tongue-in-cheek and just more subtle than I give HN credit for. Please.

dolmen2• 8 months ago

AI are good at JS because basically there is a ton of JS code available publicly without usage restriction: the JS code published to be executed in your browser. Most of JS code attached to web pages has no explicit license, but the implicit license is that anyone can download it and run it. Same for HTML and CSS. So using that public code to train models is a no brainer.

morshu90015• 8 months ago

Same reason AIs also use Python and DBMSes offer JS or Py UDFs easily, interpreted languages take no build time and are more portable. JS is also very popular.

Might also be a context window thing. Idk how much boilerplate C# has, but others like Java spam it.

mokarma2• 8 months ago

Atwood’s Law

kuekacang• 8 months ago

One other angle yet mentioned: JS is browser native. No matter how slow it is, browser is now the LCD. Similar server-client codebase, while ugly, is another plus.

jitl2• 8 months ago

There’s like 100x more JS developers than C# developers. JS can also run code very quickly, where with an AOT language, you need to AOT compile it. For tool calls, eval-as-a-service, running in browser JS is far ahead of C#.

mrsmrtss3• 8 months ago

So, everyone who can hack some JS is now a developer? The '100x' claim is obviously exaggerated. C# is certainly one of the most used programming languages there is.

You can run also C# code very quickly, but have the option (but not the need) to AOT compile it. I would say the only real edge JS has is the ability to run natively in the browser. It was built for that purpose, and in my opinion, that is where it should have stayed.

aizk4• 8 months ago

I thought c# was a dead language at this point?

mrsmrtss3• 8 months ago

You must have been living under a rock. C# is one of the most popular languages out there and it's better than ever.

greatNespresso• 8 months ago

Looks like a good time to try learning Zig again

rcarmo• 8 months ago

Neat. I just started using bun as my default "batteries included" JavaScript engine, so it's nice they're getting this boost.

shrubble• 8 months ago

There's no reason to run agents on expensive AI platforms or on GPUs - when you can have the AI create an agent in JS and thus runs with very high performance and perfect repeatability on far less expensive CPUs.

At the very least there must be some part of the agent tasks that can be run in JS, such as REST APIs, fetching web results, parsing CSV into a table, etc.

awesome_dude2• 8 months ago

Am I missing something - I thought that GPUs are for training the weights

Being able to create an agent in any language to run on any hardware has always been possible hasn't it?

int_19h• 8 months ago

Agents already do this exact thing, except that the go-to language for Claude to write one-off scripts in is usually Python.

s-mon• 8 months ago

Congratulations to the team. Knowing some of the folks on the Bun team I can not say I am surprised. They are the top 0,001% of engineers, writing code out of love. I’m hugely bullish on Anthropic, this is a great first acquisition.

qjack• 8 months ago

Anthropic has been trying to win the developer marketshare, and has been quite successful with Claude Code. While I understand the argument that this acquisition is to protect their usage in CC or even just to acquire the team, I do hope that part of their goal is to use this to strengthen their brand. Being good stewards of open source projects is a huge part of how positively I view a company.

Wowfunhappy• 8 months ago

Being good stewards of open source projects is a huge part of how positively I view a company.

Maybe an easier first step would be to open source Claude Code...?

Aeolun8• 8 months ago

I think because their models are open (e.g. CC can send any instruction and it’ll use your max plan), they need to keep the code obfuscated to prevent people from sending everybody and their mother through that API.

Codex has the opposite issue. It has an open client, which is relatively pointless, because it will accept only one system prompt and one prompt only.

grim_io• 8 months ago

Maybe they just like to work together *shrug*.

devops000• 8 months ago

Shopify should buy Ruby on Rails because they depends on it

hu35• 8 months ago

didn't they try a hostile takeover of the ruby gems thing (forgot the name)?

noodletheworld• 8 months ago

If claude code starts having ads for bun in the code it generates, I am never using it again.

To some degree have “opinionated views on tech stacks” is unavoidable in LLMs, but this seems like it moves us towards a horrible future.

Imagine if claude (or gemini) let you as a business pay to “prefer” certain tech in generated code?

Its google ads all over again.

The thing is, if they own bun, and they want people to use bun, how can they justify not preferencing it on the server side?

…and once one team does it… game on!

It just seems like a sucky future, that is now going to be unavoidable.

javierhonduco• 8 months ago

Wondering to what degree this was done to support Anthropic’s web crawler. Would assume that having a whole JS runtime rather than just a HTTP client could be rather useful. Just hypothesising here, no clue what they use for their crawler.

blixt• 8 months ago

Extrapolating and wildly guessing, we could end up with using all that mostly idle CPU/RAM (the non-VRAM) on the beefy GPUs doing inference on agentic loops where the AI runs small JS scripts in a sandbox (which Bun is the best at, with its faster startup times and lower RAM use, not to mention its extensive native bindings that Node.js/V8 do not have) essentially allowing multiple turns to happen before yielding to the API caller. It would also go well with Anthropic's advanced tool use that they recently announced. This would be a big competitive advantage in the age of agents.

intrasight• 8 months ago

I almost read this as anthropic will be using our idle CPU/GPU resources for their own training tasks ;)

mcdow• 8 months ago

From the comments here it sounds like most people think the amount Anthropic paid for the company was probably not much more than the VC funding which Bun raised.

How would the payout split work? It wouldn’t seem fair to the investors if the founder profited X million while the investors get their original money returned. I understand VC has the expectation that 99 out of 100 of investments will net them no money. But what happens in the cases where money is made, it just isn’t profitable for the VC firm.

What’s to stop everyone from doing this? Besides integrity, why shouldn’t every founder just cash out when the payout is life-changing?

Is there usually some clause in the agreements like “if you do not return X% profit, the founder forfeits his or her equity back to the shareholders”?

kevmo314• 8 months ago

Probably not much more than their valuation, which is the key difference since the investor will still get a net return.

deepdarkforest• 8 months ago

All VC's have preferred shares, meaning in case of liquation like now, they get their investment back, and then the remainder gets shared.

Additionally, depending on round, they also have multiples, like 2x meaning they get at least 2x their investment before anyone else gets anything

taf2• 8 months ago

okay so does that mean openai buys deno?

_andrei_• 8 months ago

All vendors will have to implement test time code execution, solution exploration, etc. as it's a low hanging fruit with huge gains, so I see it as a great hire. Love Bun, happy for you guys!

rashkov• 8 months ago

Do you mean train time?

Computer0• 8 months ago

So, what if Claude Code starts using Bun in all applicable situations? If model providers train their models to use a tech stack beneficial to their business interests?

terryds• 8 months ago

Wow.

hungryhobbit2• 8 months ago

But will they fix command line autocompletions?

fud1012• 8 months ago

So this is a rug pull we were afraid of? Bun got me into javascript ecosystem after years of hating on it. This sucks.

wavemode• 8 months ago

To be honest, I never thought of Bun as something that someone would buy or invest in. What product do they sell?

notnullorvoid4• 8 months ago

I am more shocked about the origin story compared to the acquisition.

Almost five years ago, I was building a Minecraft-y voxel game in the browser. The codebase got kind of large, and the iteration cycle time took 45 seconds to test if changes worked. Most of that time was spent waiting for the Next.js dev server to hot reload.

Why in the hell would anyone be using Next.js to make a 3D game... Jarred has always seemed pretty smart, but this makes no sense. He could've saved so much time and avoided building a whole new runtime by simply not using the completely wrong tool for the job.

mayo369• 8 months ago

Maybe same for anthropic, they can simply write agent using Rust/Go. Instead they decide to buy and develop a JavaScript runtime.

nly2• 8 months ago

If anything this seems to be a huge victory for Zig, since Bun is mostly written in Zig.

qeternity• 8 months ago

These are completely different. Agents (aside from the model inference) are not CPU bound. You gain much more by having a wider user base than whatever marginal CPU cycles you would gain in Rust/Go.

Video games are of course a different story.

someguyiguess14• 8 months ago

My thinking is that they’re trying to capture that market for JavaScript before another AI company does. To put it bluntly they want to capture the revenue generated by writing JavaScript code, which is currently being captured by independent JavaScript developers. The reason for a JavaScript is that is the most ubiquitous language, and id guess there are more jobs available for JS/node than any other language. Of course, as a JavaScript developer, this may just be my paranoia. <sweats profusely>

Aeolun8• 8 months ago

He could've saved so much time and avoided building a whole new runtime by simply not using the completely wrong tool for the job.

True, but where is the fun in that?

cryptonym• 8 months ago

Where is the fun in next.js?

mock-possum2• 8 months ago

Most people use what they know. You start out that way, and if it turns out to be good, you can always do a v2

notnullorvoid4• 8 months ago

Yes, but there are obvious limits to that. This is like someone who knows how to bake wanting to build a car, so they start making it out of dough.

johncolanduoni6• 8 months ago

He may have been serving a game in a canvas hosted in a Next.js app, but have done all the actual game (rendering, simulation, etc.) in something else. That’s a decent approach - Next can handle the header of the webpage and the marketing blog or whatever just fine.

komali25• 8 months ago

But like... so can an index.html with a script tag? Am I missing something, where did you read that there was a lot of work involving the header or an attached marketing blog?

Tadpole91812• 8 months ago

Because he wanted to? Do you also berate the choices of people in the 4K demo scene for using too little memory?

someguyiguess14• 8 months ago

That’s kind of the opposite though. I guess if you’re saying that there’s an art to building things using the least efficient means possible just as there’s an art to being maximally efficient (like the 4k demo scene) then your point stands.

cyco130• 8 months ago

First time I see it being a net positive that someone didn't know about Vite: Bun wouldn't exist otherwise.

moritonal• 8 months ago

This take is interesting given we're all here congratulating Jarred for seeing that there was no tool to solve x so made it, and is now enjoying a likely nice payday. Be the change you want to see in the world?

PurpleRamen3• 8 months ago

It kinda reads like a case of survivorship bias. He is the one in a million to reach the good ending, despite starting with the wrong choice; though in this case, the wrong choice brought him on the road to the good ending.

Now the real question is, does the game loads significant better now, or does the performance still suck? In which case it might be more an excessive case of yak-shaving. And if yes, when can we except the release?

ramon156• 8 months ago

I don't think his goal was to get the fastest voxel engine. Most projects just start with "That's stupid... but what if I did it anyway?"

someguyiguess14• 8 months ago

I’m guessing he was probably a JavaScript developer that wanted to make a game. He began building it using what he knew and then he hit the limitations of it. Rather than switching to something else, he tried to figure out why fast compile times weren’t possible and determined that they were possible and started to build a solution for it.

torginus3• 8 months ago

That's super strange since React by its nature assumes that controls are stateless - which games definitely are not. If you render your game inside a canvas then React decides it wants to recreate your control, then your whole game restarts.

kgc• 8 months ago

Should we be porting our Python projects over to Javascript?

VerifiedReports5• 8 months ago

"Node.js compatibility & replacing Node.js as the default server-side runtime for JavaScript"

Except Node's author already wrote its replacement: Deno.

socketcluster• 8 months ago

Bun is pretty cool. I maintain a Node.js library and updated my Node.js engine version and my library just didn't work on the latest version... In frustration, I decided to try Bun for the first time... I had never used it before but my library worked straight away, no warnings, no errors. I have never seen that level of compatibility before when a library works better with an alternative engine than the one it was designed for.

I did end up fixing Node.js compatibility later but it was extra work. Felt like they just created busy-work. Node.js maintainers should stop deprecating perfectly good features and complicating their modules.

mdtrooper• 8 months ago

It is remembers to me to Arduino buy for Qualcomm. And it was not good news.

m00dy• 8 months ago

who's going to buy deno ?

pech0rin• 8 months ago

Look Bun is a great product but something hilarious about the company that is “going to replace all software developers with AI” BUYING software. You are building a product that is supposed to make software cost 0 right? Why wouldn’t you just “vibe” code yourself Bun?

fragmede2• 8 months ago

Those aren't your customers. The people that want to build things with bun are. The problem with people who already know how to code is that they have opinions if they actually read the generated code. If you sell to people who don't (for whatever reason), you face less criticism.

solumunus3• 8 months ago

I think you’re confused.

going to replace all software developers with AI

No?

building a product that is supposed to make software cost 0 right

No?

hit8run• 8 months ago

I love bun but for a cli tool: why they don’t write Claude Code in Go and call it a day?

tossandthrow• 8 months ago

Maybe now Claude will not assume that I use npm, and actually start using bun?

mkornaukhov• 8 months ago

That's good news. I hope this will encourage the industry to use the Zig language (and its creators to release version 1.0).

bababuu• 8 months ago

I find it a little sad, that there is almost no pushback on what a few people with deep pockets are trying to sell here. Normaly on HN an article on balcon gardening would be met with more critical thinking than this piece. Maybe instead of staring to the screen all day long take a break, think about what people with lots of money care about. And I don't judge, making money is nothing illegal. But Anthropic would be absolutely NOTHING without OSS. And then to see the kind of this effusive, submissive admiration and gratitude for their js wrapper thing makes me sick to my stomach.

tonyhart7• 8 months ago

why not Antrophic just fork or make a clone Bun themselves????

bluelightning2k2• 8 months ago

Since when is a CLI tool like this a sufficiently demanding technical project that it needs to buy the runtime just to get sufficient support?

This just isn't the hard part of the product.

Like if I was building a Claude Code competitor and I acquired bun, I wouldn't feel like I had an advantage because I could get more support with like fs.read?

bluelightning2k2• 8 months ago

I think this acquisition in reality has more to do with developer goodwill? And a little to do with the shell game of making these AI companies hard to value because they collect assets like this.

aperture147• 8 months ago

Why don't they use their self-acclaimed SE-replacing AI coding bot to fork Bun and called it AnthroBun instead of hiring actual engineers behind Bun?

elAhmo• 8 months ago

Anthropic has direct incentive to keep Bun excellent.

Huh, this feels very odd to read and buying a company outright is definitely not the only way to push Bun to be excellent. Contributing to Bun from their developers, becoming a sponsor, donating through other means, buying 'consulting services' or similar, or even forking it and keeping it up to date would all be also steps towards keeping the Bun excellent.

This is vendoring a dependency on steroids, and first moment interests of community are not aligned with what Antropic needs, it will be interesting to see how this unfolds. History has thought us that this will end up with claims in the blog post not holding much weight.

smotched• 8 months ago

since Anthropic is one of the only companies using the Bun Runtime, not just the bundler like most do, they want to make sure the runtime stays the focus. This is good for both companies and us tbh since they wont switch focus to whats popular at the moment

kunley• 8 months ago

So will Bun devs now be obliged to stop coding and only manage ai-driven code, like Anthropic devs say they are?

Or perhaps they have in their agreement that Anthropic's own rules don't apply to them?

Serious question, in all this madness

baxuz2• 8 months ago

AI slop lovers both of them.

odyssey7• 8 months ago

Proper tail calls for the win! Hopefully Google, now in its AI race, decides to give V8 its due.

dgellow2• 8 months ago

Congrats to the Bun team, what a wild ride! Is that the first major zig acquisition?

lionkor• 8 months ago

Bun will ship faster.

What? Oh, lots of slop code?

soapdog2• 8 months ago

oh, I really dislike that. I don't want AI companies encroaching more in my development workflow. Used to really enjoy Bun, but don't want support Anthropic at all. Will switch back to another runtime.

esjeon• 8 months ago

Yeah, I really get that. I’ve been a fan of zig and bun since their inception, but, AI corp deep in the dev chain? I feel uncomfortable, because no one knows when they’ll start steering things into weird directions.

ignoramous6• 8 months ago

AI corp deep in the dev chain? I feel uncomfortable ...

tbf, Google has long been an AI corp. The Big Labs are trying to get in to other products/businesses just like Google did.

phplovesong• 8 months ago

RIP Bun. I guess a bet on deno was the right bet.

hu35• 8 months ago

deno is VC funded which means enshitification is expected.

It would be ironic if deno ended up having more builtin AI bloat despite Bun being the one owned by an AI company. But I wouldn't be surprised.

simgt• 8 months ago

We're meant to all be 100x more productive with Claude Code but

- Anthropic can't write its TUI app in anything else more suitable than Javascript

- They feel the need to buy a portion of their software supply chain

someguyiguess14• 8 months ago

This explains why Claude started transpiling & running JavaScript code! Yesterday, when I asked it to generate a document for me in JavaScript, it generated the JavaScript and then ran it to generate a document. I had never actually seen it compile and run any code before. It only would ever output code and either use the shell (Claude code) to run it on my local computer or allow me to copy and paste it.

informal007• 8 months ago

Maybe they want to catch up the steps of Antigravity.

Running code is absolutely going to happen for coding assistant.

danirogerc• 8 months ago

Hopefully it doesn't push other LLM companies to go the same route.

gaws4• 8 months ago

It absolutely will.

imjacobclark2• 8 months ago

Owning your runtime is not about developer experience at the scale of Claude Code, it’s about your execution-surface area and the control you have over it.

Agentic systems are no longer just model-driven — they are increasingly runtime-driven through tools, sandboxes, and orchestration layers. When agents are writing code, executing tests, calling external tools, and validating outcomes, the reliability of the entire system becomes a function of the runtime and environment, not just the model.

Controlling the runtime gives Anthropic vertical control across:

- Packaging and distribution - Execution semantics - Performance characteristics - Security surface area - Operational stability

Of course, owning a JavaScript runtime does not magically make runtime deterministic. The dominant sources of variability still sit lower in the stack: OS behaviour, native dependencies, filesystem semantics, scheduling, hardware differences, and network effects. Runtime ownership is necessary, but not sufficient, for true runtime determinism.

What this does signal is a strategic shift in where value is being captured.

Model capability is no longer the only critical layer.

The execution plane is becoming just as strategic too, can see this in ChatGPT 5’s dynamic model routing capability as well as ecosystem wide Tool Calling and MCP adoption, which are all aimed at increasing LLM determinism through traditional software stacks.

Vertical integration here looks far less like a tooling move and far more like a control-plane strategy: consolidate the stack, reduce dependency entropy, and shrink the surface area where behaviour can diverge.

Intelligence may live in the model, but reliability, scalability, and trust are increasingly properties of the system that executes it.

torginus3• 8 months ago

So you're saying Anthropic is making it's own AI-based AWS, like OpenAI is trying to do AI social media?

imjacobclark2• 8 months ago

not quite, just the runtime above the os layer

theodric• 8 months ago

That's nothing. I just bought four buns yesterday!

Anthropic acquires Bun

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