@bunjavascript

Bun is a fast, all-in-one toolkit for installing, bundling, running and testing JavaScript & TypeScript. To install: `npm i -g bun`

bun.com
Joined July 2022
  • Tweets4.2K
  • Following7
  • Followers83.1K
1KMedia
Bun
@bunjavascript2 Dec 2025
Bun is joining Anthropic! bun.com/blog/bun-joins-anthr…

Bun is joining Anthropic

Bun has been acquired by Anthropic. Anthropic is betting on Bun as the infrastructure powering Claude Code, Claude Agent SDK, and future AI coding products & tools.

bun.com
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@bunjavascript5h
Replying to @shubhporwal24
we don’t have publishing access
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@bunjavascript6h
We needed to get this release out tonight , so we couldn't include `bun lint` yet. bun lint is available via `bun upgrade --canary` though
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@bunjavascript6h
Bun v1.4.4 - Fixes 271 issues, addressing 544 👍 - `bun fmt` is a fast Prettier-compatible code formatter - `bun check` gets 1.4x - 7.8x faster - New in Bun.SQL & WebSocket - Security fixes, including for Brotli, TLS certs, HTTP/3, and more bun.com/blog/bun-v1.4.4

Bun v1.4.4

Fixes 271 issues, addressing 544 👍. bun fmt, a Prettier-compatible formatter built into Bun that is 3x to 6x faster than oxfmt, bun check is 1.4x to 7.8x faster on large projects, bun install...

bun.com
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@bunjavascript11h
Bun v1.4.4 is compiling
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@bunjavascript17h
Bun v1.4.4 will be released this evening with a fix for this and for the Brotli issue. Both fetch() and Bun.serve() did not and continue to not enable HTTP/3 by default.
John Althouse@4A413320h
Sorry everyone... We're announcing a 0-Day vuln in QUIC that allows anyone to remotely turn off a server running these libraries. I swear we didn't plan this. foxio.io/blog/header-accordi…

Header Accordions: QPACK amplification attacks against HTTP/3 servers - FoxIO | Cyber Innovation

We solve the world’s toughest cyber challenges—creating breakthrough technology and embedding it into the systems that run everything.

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Bun
@bunjavascriptOct 21
Replying to @rydgel @jarredsumner
anime
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@bunjavascriptOct 20
Replying to @prathamghaywat
it’s patched in canary now but not yet in a release
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Jarred Sumner
@jarredsumnerOct 19
In the next version of Bun bun check gets 1.7x - 7x faster
Benchmark chart for bun check, Bun's built-in TypeScript type checker. It compares Bun canary, Bun 1.4.3 and tsc 7.0.2 on four projects, showing time and peak memory for a full type check. mui docs: canary 1.31s, 1.5 GiB. Bun 1.4.3 9.31s, 9.6 GiB, 7.1x slower. tsc 18.04s, 8.3 GiB, 13.8x slower. t3code server: canary 1.47s, 1.5 GiB. Bun 1.4.3 4.53s, 1.6 GiB, 3.1x slower. tsc 22.02s, 7.1 GiB, 15.0x slower. supabase studio: canary 0.63s, 1.6 GiB. Bun 1.4.3 1.67s, 1.9 GiB, 2.7x slower. tsc 8.98s, 4.5 GiB, 14.3x slower. mikro-orm: canary 1.24s, 1.6 GiB. Bun 1.4.3 2.15s, 2.0 GiB, 1.7x slower. tsc 13.41s, 6.8 GiB, 10.8x slower. Benchmarked on a 64-core machine (EPYC 9R14, Linux x64). No cache, default settings.

ALT Benchmark chart for bun check, Bun's built-in TypeScript type checker. It compares Bun canary, Bun 1.4.3 and tsc 7.0.2 on four projects, showing time and peak memory for a full type check. mui docs: canary 1.31s, 1.5 GiB. Bun 1.4.3 9.31s, 9.6 GiB, 7.1x slower. tsc 18.04s, 8.3 GiB, 13.8x slower. t3code server: canary 1.47s, 1.5 GiB. Bun 1.4.3 4.53s, 1.6 GiB, 3.1x slower. tsc 22.02s, 7.1 GiB, 15.0x slower. supabase studio: canary 0.63s, 1.6 GiB. Bun 1.4.3 1.67s, 1.9 GiB, 2.7x slower. tsc 8.98s, 4.5 GiB, 14.3x slower. mikro-orm: canary 1.24s, 1.6 GiB. Bun 1.4.3 2.15s, 2.0 GiB, 1.7x slower. tsc 13.41s, 6.8 GiB, 10.8x slower. Benchmarked on a 64-core machine (EPYC 9R14, Linux x64). No cache, default settings.

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@bunjavascriptOct 18
Replying to @uwukko
Co-Authored-By: Bun v1.5.0 (JavaScript runtime, bundler, package manager, test runner, type checker, code formatter, and linter) <bun@localhost>
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@bunjavascriptOct 15
In the next version of Bun `bun lint --staged` is a builtin alternative to lint-staged
Graphic for bun fmt and bun lint --staged. Format and lint only what you're committing. One line in a git hook, nothing to install. Step 1, create this file: .git/hooks/pre-commit, a plain text file made executable with chmod +x, containing "#!/bin/sh" and "bun fmt --staged && bun lint --staged". Step 2, commit: a terminal runs git commit -m "add cart". bun fmt prints "src/cart.ts" and "Formatted 1 file, 0 unchanged [8.10ms]", with a sticker reading "re-staged". bun lint then prints a code frame pointing at a debugger statement in src/cart.ts line 2, "error: Unexpected 'debugger' statement. no-debugger", "1 problem (1 error, 0 warnings)" and "Linted 1 file [7.94ms]". A stamp reads "commit blocked".

ALT Graphic for bun fmt and bun lint --staged. Format and lint only what you're committing. One line in a git hook, nothing to install. Step 1, create this file: .git/hooks/pre-commit, a plain text file made executable with chmod +x, containing "#!/bin/sh" and "bun fmt --staged && bun lint --staged". Step 2, commit: a terminal runs git commit -m "add cart". bun fmt prints "src/cart.ts" and "Formatted 1 file, 0 unchanged [8.10ms]", with a sticker reading "re-staged". bun lint then prints a code frame pointing at a debugger statement in src/cart.ts line 2, "error: Unexpected 'debugger' statement. no-debugger", "1 problem (1 error, 0 warnings)" and "Linted 1 file [7.94ms]". A stamp reads "commit blocked".

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@bunjavascriptOct 15
Replying to @YousefAmanDev
yes!
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@bunjavascriptOct 15
bun lint builds on top of: - TypeScript’s parser and type checker, ported to Rust - Lint rules ported from oxlint: unicorn, jest, vitest, jsx-a11y, next and promise - Lint rules ported from ESLint, typescript-eslint, eslint-plugin-react, -import and -react-hooks Big thanks to those projects!
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@bunjavascriptOct 15
Replying to @DarkModeDingo
we need to film still
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@bunjavascriptOct 15
Replying to @proxy_vector
yes!
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@bunjavascriptOct 15
You can see the complete list of over 1,000 builtin lint rules here bun.com/docs/lint/rules

Lint rules | Bun Docs

Every rule built into bun lint

bun.com
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@bunjavascriptOct 15
Large production apps often need many custom lint rules, and that’s why bun lint supports eslint plugins. Under the hood, this is powered by the same parser and AST used by `bun check`, which is designed for TypeScript compatibility with additional performance optimizations.
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@bunjavascriptOct 15
In the next version of Bun bun lint is a 26x faster ESLint-compatible linter with over 1,000 builtin rules - reads eslint & oxlint configs.
Poster for bun lint, an ESLint-compatible linter built into Bun. Headline: 26x faster than ESLint. Table of lint times on real projects, each with its own config and plugins, bun lint vs ESLint: shadcn/ui 2.1 s vs 90.4 s (43x), chakra-ui 0.59 s vs 22.6 s (38x), vscode 15.8 s vs 404 s (26x), mastodon 6.6 s vs 100 s (15x), playwright 4.9 s vs 53.4 s (11x). On vscode, 9,823 of 9,826 messages are identical. 99.6% of ESLint's tests pass. 99.8% of oxlint's tests pass. 2x faster than oxlint with 3x less memory. 1,021 rules built in, including type-aware rules.

ALT Poster for bun lint, an ESLint-compatible linter built into Bun. Headline: 26x faster than ESLint. Table of lint times on real projects, each with its own config and plugins, bun lint vs ESLint: shadcn/ui 2.1 s vs 90.4 s (43x), chakra-ui 0.59 s vs 22.6 s (38x), vscode 15.8 s vs 404 s (26x), mastodon 6.6 s vs 100 s (15x), playwright 4.9 s vs 53.4 s (11x). On vscode, 9,823 of 9,826 messages are identical. 99.6% of ESLint's tests pass. 99.8% of oxlint's tests pass. 2x faster than oxlint with 3x less memory. 1,021 rules built in, including type-aware rules.

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Makisuo
@makisuoOct 13
Moved an important API from Node → @bunjavascript Latency p50: −25% p95: −60% p99: −80% Resources Memory: −63% CPU: −25%
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@bunjavascriptOct 13
Replying to @proxy_vector
yes. if you run into any problems, please file an issue in our github repo
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@bunjavascriptOct 13
Around 47k of the formatter's ~100k lines are based on Oxc's formatter (and Biome's, since Oxc's was based on Biome's), and it's tested against Prettier's own test suite. Big thanks to those projects!
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