It's weird their promotional video repeats "you can do <million things> without installing dependencies", if I want headless browser testing is that wrong to install a project that offers that?
Why would I want everything reimplemented in this massive binary? Why would Bun be anymore in touch with nuances of all these different technologies then individual projects dedicated to their own speciality?
JS Runtime, Package Manager, Test Runner (both unit and headless browser), Bundler, JSX, PosgreSQL/MySQL/SQLite drivers, S3 client, Redis client, Formatter, Linter, etc.
Not to mention parsers for YAML, TOML, Markdown which are easily three separate projects worth of complexity in their own right.
I guess one clear downside is to get all these great features they're pushing for 1.4 you needed to wait until everything was ready. Given 1.3 was pushed out in October 2025, a 10 month release cycle across so many large technologies is tough. Before you give a pass because of the Rust rewrite Bun 1.2 was released in January 2025
I have to respect Jarred knows how to work the algorithm, 10 carefully crafted X teaser posts for this release spaced out over 72 hours https://xcancel.com/jarredsumner
> Why would I want everything reimplemented in this massive binary? Why would Bun be anymore in touch with nuances of all these different technologies then individual projects dedicated to their own speciality?
It's funny because the top article on HN is about a malicious rust crate package, and people keep making comparisons to js/npm and how both language suffer from frequent security issues because they have weak std libs.
I saw a post recently about how LLMs are much more effective in Ruby on Rails because it's batteries included, so you don't get so many implementation details crapping up the context window.
I assume the same benefit applies to humans as well!
I am not into the Ruby on Rails world, but I find LLMs much more effective with powerful type systems like Typescript. Especially if you nudge it to keep things strict and (statically) eliminate invalid states. Do they use similar systems (build-time typing) for Ruby?
When the LLM can verify its own output by running static analysis they produce better results. They also seem to understand type definitions and avoid going to the source which, in theory, should reduce context size.
Something that frustrates me about that discourse is that people argue about the mere existence of dependencies but all 'supply chain' (1) attacks are issues over when dependencies change. Dynamic systems are harder to reason about than static ones.
(1) scare quotes because I think it's dumb for us software people to call code we picked up on the side of the road part of a 'supply chain' like that means anything.
Its strange how flip floppy the JS ecosystem is, because go back literally 1-3 years or so and the BIGGEST complaint was the lack of a standard library and having to use a package for everything.
But now that Bun is actually doing it its somehow bad? Its also still open source, so those implementations you mention need dedicated teams can still get the attention they need by the community if needed.
I'm on the side that I'd actually prefer if node included more out of the box and we could drastically cut down on the number of packages we need due to the amount of supply chain attacks that happen on packages in the node ecosystem.
Is that flip-flopping or just different developers having different preferences? Those who complain now would have had no reason to complain back then, and vice versa
Out of the things you mentioned I think the following make totally sense to be included in a language runtime like this:
JavaScript runtime (obviously), package manager, test runner for unit tests, bundler, JSX, SQLite bindings, formatter, linter, YAML and TOML parsers. Maaaaybe even a Markdown parser and HTML5 parser. Definitely JSON, CSV and XML parsers.
I.e. similar to Python. Though Python is a bit of an incoherent mess. If you have all these you need them to be coherent.
“ Why would I want everything reimplemented in this massive binary? “
This isn’t about what individual developers would want but what is most beneficial to Anthropic and claude code. They are likely using Bun as a vehicle for standardizing and enriching local user environments in order to address common tasks that claude generally writes bespoke scripts to accomplish.
> It's weird their promotional video repeats "you can do <million things> without installing dependencies",
A couple years ago a common complaint was that the JavaScript ecosystem relied too heavily on dependencies for everything. Remember the left-pad incident where the developer deleted the popular dependency out of protest for reasons I can even remember? Or when colors.js was sabotaged to break everything that depended on it? The node-ipc package was sabotaged to delete files on developer’s machines. Then we had a wave of supply chain attacks that tried to insert malware into build scripts of popular dependencies.
So the ecosystem started moving toward more batteries-included style development in response.
The complaint was micro-dependencies and huge sprawling trees. What was needed was quality dependencies on the level of SDL, ffmpeg, libcurl, where one domain is solved well and the focus is on API stability and good implementation. Not a battery included type of things.
Some of these feel like solved problems effectively, so having them in the standard library is nice (at the expense of keeping these forever for backwards compatibility once a new tech replaces it). I do think having a larger standard library for common things (like golang) is the way to go. If a dependency seems to basically be installed by default everywhere, maybe it should go in the standard library.
I always thought Bun's approach was to be the JS runtime with a large well-designed std-library, this isn't really new. It's nice to have a choice of a more or less-featured runtime depending on the project's requirements -- if size and complexity are an issue, there's a variety to choose from.
Things like headless browsers are really annoying to include in FaaS environments, but are super useful. If they're in the runtime binary already, that'd be great.
I for one prefer batteries-included. Decision fatigue for every cobbled together package takes its toll. Having a single, trustworthy, good-enough solution for so many things makes my life easier.
I've still yet to run into any enterprise project using bun in the wild. It really feels like something entirely contained within startups that would choose wildly inappropriate tech like next.js.
Add in the influencer dev brainrot culture and you get these VC backed efforts to privatized publicly important projects (node.js) under control of quite evil people that have zero record of helping others.
I recently pivoted to Rust for the backend development, after getting tired of the nodejs ecosystem fragmentation and how fragile things feel. Bun seems very interesting since it allows you to do so many things without pulling in 3rd party libraries and bundlers? Is anybody using it instead of nodejs? how's the experience so far? I might have to give it a try.
Yes, I know there's probably better options than Rust for building APIs, but I wanted to learn it, so why not?
The most appealing thing of Go to me is the good batteries including tooling. I don't use it much outside of little personal projects where I really don't want to deal with dependencies and want a small binary.
I'm using it, though I'm leery of how the project is run. It's been great, to be honest. I have been able to build very low-dependency projects quite quickly. Bun's documentation is decent, and its underlying features are performant.
This is a huge win for Bun & Anthropic. I've been keeping an eye on Bun development cycle since they announced the Rust rewrite and the huge drama and backlash it generated. They seem to be proving the skeptics wrong with this release.
For me, notably absent from the release changelog and accompanying YouTube video they were excited to trumpet in the blog back in July, and the claim (still) this took 11 days. It's August 20th.
I think around $300-400k, but that does not include the github issue/pr/ci stuff that runs continuously, which could double or triple it. Somewhere, the first two weeks were said to be about $200k.
Am I the only one starting to get annoyed by Bun just due to all the surrounding drama? I was genuinely surprised this was an actual link about an update - my gut inclination opening that was Jarred probably decided to rewrite Bun to JavaScript to stay pure or something like that.
I know we're all using AI, but Bun seems like the one singular project where there's just been a crazy increase in the amount of output, a 10x on the 10x.
slightly aside, but I find it worrying that our industry treats a lot of cannon events in stride and don't organize around that idea or to mitigate the risks around that idea.
things that everybody basically just complained but ended up working out fine,
- Bun rust rewrite.
- Elon Musk firing 80% of twitter by stack ranking employees by code committed
- autocompletion basically just taking over everyone
maybe I'm just taking extremely outlier outcomes. but it is still fascinating to see people complain about how LLMs don't think
While it has been used by Anthropic, the main question is if it works in other Bun's 1.3 production settings. Ignoring all the improvements, if it does work and no major bug or problems occurred, We are in for some management top down "Rewrite it in Rust" action over the next few years. And perhaps even worst, management will believe in Claude feed into Claude development.
This isn't so much about Bun or Node.js any more. It is the battleground for AI and non-AI coding.
From the release video, something catching my attention:
> In Bun 1.4, I rewrote Bun in Rust. [...] I did it in 11 days, using Claude Code, and wrote about how, in our blog.
Everything else in the video is phrased as "we", and even the section in the blog post is "We rewrote Bun in Rust"[1].
There's no question Jarred did the work and deserves enormous credit for it. I just found the contrast interesting, because the video explicitly frames the rewrite as "I", whereas the rest of the release frames it as "we".
I filled a bug https://github.com/oven-sh/bun/issues/34588 and a PR but my name is not on the blog :(
Why would I want everything reimplemented in this massive binary? Why would Bun be anymore in touch with nuances of all these different technologies then individual projects dedicated to their own speciality?
JS Runtime, Package Manager, Test Runner (both unit and headless browser), Bundler, JSX, PosgreSQL/MySQL/SQLite drivers, S3 client, Redis client, Formatter, Linter, etc.
Not to mention parsers for YAML, TOML, Markdown which are easily three separate projects worth of complexity in their own right.
I guess one clear downside is to get all these great features they're pushing for 1.4 you needed to wait until everything was ready. Given 1.3 was pushed out in October 2025, a 10 month release cycle across so many large technologies is tough. Before you give a pass because of the Rust rewrite Bun 1.2 was released in January 2025
I have to respect Jarred knows how to work the algorithm, 10 carefully crafted X teaser posts for this release spaced out over 72 hours https://xcancel.com/jarredsumner
It's funny because the top article on HN is about a malicious rust crate package, and people keep making comparisons to js/npm and how both language suffer from frequent security issues because they have weak std libs.
I assume the same benefit applies to humans as well!
When the LLM can verify its own output by running static analysis they produce better results. They also seem to understand type definitions and avoid going to the source which, in theory, should reduce context size.
(1) scare quotes because I think it's dumb for us software people to call code we picked up on the side of the road part of a 'supply chain' like that means anything.
But now that Bun is actually doing it its somehow bad? Its also still open source, so those implementations you mention need dedicated teams can still get the attention they need by the community if needed.
I'm on the side that I'd actually prefer if node included more out of the box and we could drastically cut down on the number of packages we need due to the amount of supply chain attacks that happen on packages in the node ecosystem.
https://en.wiktionary.org/wiki/Goomba_fallacy
Otoh should a standard lib give you absolutely everything? Probably not. There needs to be a line somewhere.
Right now Bun’s policy on this seems to be "whatever Jarred feels like should be in there".
This is the main draw. Everything he implemented was fast and minimalist and he usually implements a standardized api (web apis, esbuild bundler api).
The opinionated stuff is usually very common sense.
Most of the libraries OC mentions are things you would just like to be as fast as possible above all else.
I feel like nobody complained that you needed to install a dependency to do headless browser testing for example.
JavaScript runtime (obviously), package manager, test runner for unit tests, bundler, JSX, SQLite bindings, formatter, linter, YAML and TOML parsers. Maaaaybe even a Markdown parser and HTML5 parser. Definitely JSON, CSV and XML parsers.
I.e. similar to Python. Though Python is a bit of an incoherent mess. If you have all these you need them to be coherent.
This isn’t about what individual developers would want but what is most beneficial to Anthropic and claude code. They are likely using Bun as a vehicle for standardizing and enriching local user environments in order to address common tasks that claude generally writes bespoke scripts to accomplish.
You have more options, not less, you can still use the external dependencies.
A couple years ago a common complaint was that the JavaScript ecosystem relied too heavily on dependencies for everything. Remember the left-pad incident where the developer deleted the popular dependency out of protest for reasons I can even remember? Or when colors.js was sabotaged to break everything that depended on it? The node-ipc package was sabotaged to delete files on developer’s machines. Then we had a wave of supply chain attacks that tried to insert malware into build scripts of popular dependencies.
So the ecosystem started moving toward more batteries-included style development in response.
Add in the influencer dev brainrot culture and you get these VC backed efforts to privatized publicly important projects (node.js) under control of quite evil people that have zero record of helping others.
https://youtu.be/i38DgEuaJwM?si=6oKAysKoRDPCihsL&t=176
Yes, I know there's probably better options than Rust for building APIs, but I wanted to learn it, so why not?
Maybe run it as process 1 in a future ClaudeOS.
How about you make a video on something you published and see how you look?
A year from now folks will be; I can’t use it anymore it’s too unreliable but for now keep looking the other way.
Hey, did the memory leak really solve with slop rewrite?
How is this even possible?
I know we're all using AI, but Bun seems like the one singular project where there's just been a crazy increase in the amount of output, a 10x on the 10x.
How are they doing this?
Jarred spins it as "pre-release" [1] but it was pre-embargo.
[1]: https://bun.com/blog/bun-in-rust#loops-that-write-review-cod....
slightly aside, but I find it worrying that our industry treats a lot of cannon events in stride and don't organize around that idea or to mitigate the risks around that idea.
things that everybody basically just complained but ended up working out fine,
- Bun rust rewrite. - Elon Musk firing 80% of twitter by stack ranking employees by code committed - autocompletion basically just taking over everyone
maybe I'm just taking extremely outlier outcomes. but it is still fascinating to see people complain about how LLMs don't think
Comments here 3 months ago are quite something: https://news.ycombinator.com/item?id=48132488
This isn't so much about Bun or Node.js any more. It is the battleground for AI and non-AI coding.
> In Bun 1.4, I rewrote Bun in Rust. [...] I did it in 11 days, using Claude Code, and wrote about how, in our blog.
Everything else in the video is phrased as "we", and even the section in the blog post is "We rewrote Bun in Rust"[1].
There's no question Jarred did the work and deserves enormous credit for it. I just found the contrast interesting, because the video explicitly frames the rewrite as "I", whereas the rest of the release frames it as "we".
[1] https://bun.com/blog/bun-v1.4#we-rewrote-bun-in-rust