@bunjavascript profile picture
Bun @bunjavascript

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

Joined July 2022
  • Tweets 3,977
  • Following 7
  • Followers 79,744
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Bun
@bunjavascript
2 Dec 2025
Bun is joining Anthropic! bun.com/blog/bun-joins-anthrโ€ฆ

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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prisma.io/blog/bun-rust-rewrโ€ฆ

We put Bun's Rust rewrite in production on Prisma Compute

Why Prisma Compute's public beta runs on Bun's Rust rewrite canary: the memory and connection-pool failures we hit on stable Bun, and what changed.

prisma.io
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Bun retweeted
Sรธren Bramer Schmidt
@sorenbs
Jun 10
All developers and agents deserve a powerful runtime ๐ŸŽ‰ We put the @bunjavascript @rustlang rewrite in production and are super excited for the future of the project.
LD1117 low drop positive voltage regulator@aqrln
Jun 10
enough with the tyranny of V8 isolates, everyone now gets a real x86_64 VM but without cold starts and with serverless DX, ergonomics and economics (except cheaper than the competition) blog posts incoming!
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Hot take after 2 years of Bun in production: the DX is good enough that I'd pick it over Node even for "boring" enterprise work. @bunjavascript @elysiaJS @DrizzleORM is the most fun I've had shipping backend in years.
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Bun retweeted
Jaid
@JaidCodes
May 27
Heartbreaking: Iโ€™ve been using it intensively for a few hours now and I canโ€™t find anything wrong with the viberewritten version. Itโ€™s smaller, faster, retains 100% feature parity and didnโ€™t crash once, also no other unexpected behavior at any point.
Jarred Sumner
@jarredsumner
May 17
Replying to @nathanv246 @voidtalker @LukasHozda
bun upgrade --canary
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In the next version of Bun `Buffer.from(str, "hex")` gets 4.8x faster
bun v1.4.0 // str: 1 MIB Buffer. from(str, "hex") 4.8ร— faster than Bun 1.3.14 Bun 1.4.0 116.2 uS Node.js 25.2.1 Bun 1.3.14 also: buf write(str, "hex") into an existing Buffer - 105.5 us, vs 544.6 us in Node.js (5.2ร— faster) mitata โ€ข Apple M4 Max โ€ข Node.js 25.2.1 552.2 553.5 us lower is better

ALT bun v1.4.0 // str: 1 MIB Buffer. from(str, "hex") 4.8ร— faster than Bun 1.3.14 Bun 1.4.0 116.2 uS Node.js 25.2.1 Bun 1.3.14 also: buf write(str, "hex") into an existing Buffer - 105.5 us, vs 544.6 us in Node.js (5.2ร— faster) mitata โ€ข Apple M4 Max โ€ข Node.js 25.2.1 552.2 553.5 us lower is better

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In the next version of Bun `Buffer.from(str, "base64url")` gets 41x faster on large input
bun v1.4.0 // str: 1 Mib Buffer. from(str, "base64url") 41ร— faster than Bun 1.3.14 Bun 1.4.0 80.95 uS Bun 1.3.14 also: same string through "base64" - 98.66 uS, vs 326.11 us in Node.js (3.3x faster) thanks to Daniel Lemire's simdutf โ€ข mitata โ€ข Apple M4 Max 3,320 us lower is better

ALT bun v1.4.0 // str: 1 Mib Buffer. from(str, "base64url") 41ร— faster than Bun 1.3.14 Bun 1.4.0 80.95 uS Bun 1.3.14 also: same string through "base64" - 98.66 uS, vs 326.11 us in Node.js (3.3x faster) thanks to Daniel Lemire's simdutf โ€ข mitata โ€ข Apple M4 Max 3,320 us lower is better

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In the next version of Bun Bun.stringWidth() ๅค„็†ไธญๆ–‡ใ€ๆ—ฅๆ–‡ใ€้Ÿฉๆ–‡ๅญ—็ฌฆ็š„้€Ÿๅบฆๆๅ‡ไบ† 7~56 ๅ€ Bun.stringWidth() ใŒไธญๅ›ฝ่ชžใƒปๆ—ฅๆœฌ่ชžใƒป้Ÿ“ๅ›ฝ่ชžใฎๆ–‡ๅญ—ใง 7ใ€œ56 ๅ€้ซ˜้€ŸๅŒ–ใ•ใ‚Œใพใ—ใŸ Bun.stringWidth()๊ฐ€ ์ค‘๊ตญ์–ดยท์ผ๋ณธ์–ดยทํ•œ๊ตญ์–ด ๋ฌธ์ž์—์„œ 7~56๋ฐฐ ๋นจ๋ผ์กŒ์Šต๋‹ˆ๋‹ค
โฏ bun string-width.mjs clk: ~3.82 GHz cpu: Apple M4 Max runtime: bun 1.4.0 (arm64-darwin) benchmark avg (min โ€ฆ max) p75 p99 (min โ€ฆ top 1%) ------------------------------------------- ------------------------------- Bun.stringWidth - cjk 7 19.17 ns/iter 19.87 ns โ–ˆ (17.12 ns โ€ฆ 26.40 ns) 21.05 ns โ–โ–โ–โ–โ–‚โ–โ–ˆโ–ƒโ–ˆโ–โ–‚โ–ˆโ–„โ–‚โ–†โ–…โ–‚โ–…โ–‚โ–โ– Bun.stringWidth - cjk 70 30.67 ns/iter 31.01 ns โ–ˆ โ–ƒ (26.32 ns โ€ฆ 58.46 ns) 33.44 ns โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–‚โ–†โ–ˆโ–†โ–ˆโ–„โ–…โ–โ–‚โ–โ–โ– Bun.stringWidth - cjk 700 243.57 ns/iter 246.04 ns โ–ˆ (216.38 ns โ€ฆ 256.17 ns) 249.29 ns โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–‚โ–โ–โ–‚โ–„โ–‚โ–ˆโ–‚โ– Bun.stringWidth - cjk 7,000 2.42 ยตs/iter 2.43 ยตs โ–ˆ (2.38 ยตs โ€ฆ 2.44 ยตs) 2.43 ยตs โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–ˆโ–„ Bun.stringWidth - cjk 35,000 12.12 ยตs/iter 12.13 ยตs โ–ˆ (12.08 ยตs โ€ฆ 12.16 ยตs) 12.14 ยตs โ–ˆโ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–ˆโ–ˆโ–โ–ˆโ–ˆโ–โ–โ–ˆโ–ˆ bun/bench/snippets on ๎‚  main [$!

ALT โฏ bun string-width.mjs clk: ~3.82 GHz cpu: Apple M4 Max runtime: bun 1.4.0 (arm64-darwin) benchmark avg (min โ€ฆ max) p75 p99 (min โ€ฆ top 1%) ------------------------------------------- ------------------------------- Bun.stringWidth - cjk 7 19.17 ns/iter 19.87 ns โ–ˆ (17.12 ns โ€ฆ 26.40 ns) 21.05 ns โ–โ–โ–โ–โ–‚โ–โ–ˆโ–ƒโ–ˆโ–โ–‚โ–ˆโ–„โ–‚โ–†โ–…โ–‚โ–…โ–‚โ–โ– Bun.stringWidth - cjk 70 30.67 ns/iter 31.01 ns โ–ˆ โ–ƒ (26.32 ns โ€ฆ 58.46 ns) 33.44 ns โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–‚โ–†โ–ˆโ–†โ–ˆโ–„โ–…โ–โ–‚โ–โ–โ– Bun.stringWidth - cjk 700 243.57 ns/iter 246.04 ns โ–ˆ (216.38 ns โ€ฆ 256.17 ns) 249.29 ns โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–‚โ–โ–โ–‚โ–„โ–‚โ–ˆโ–‚โ– Bun.stringWidth - cjk 7,000 2.42 ยตs/iter 2.43 ยตs โ–ˆ (2.38 ยตs โ€ฆ 2.44 ยตs) 2.43 ยตs โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–ˆโ–„ Bun.stringWidth - cjk 35,000 12.12 ยตs/iter 12.13 ยตs โ–ˆ (12.08 ยตs โ€ฆ 12.16 ยตs) 12.14 ยตs โ–ˆโ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–ˆโ–ˆโ–โ–ˆโ–ˆโ–โ–โ–ˆโ–ˆ bun/bench/snippets on ๎‚  main [$!

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๐Ÿค update:
Bun in Rust Even smaller. Linux x64 -18.7 MB 21% smaller 88.5 โ†’ 69.8 MB All 6 Linux targets โ€ข another -12.0 MB on average since the previous Rust build

ALT Bun in Rust Even smaller. Linux x64 -18.7 MB 21% smaller 88.5 โ†’ 69.8 MB All 6 Linux targets โ€ข another -12.0 MB on average since the previous Rust build

Bun
@bunjavascript
May 18
Bun Smaller in Rust. macOS arm64 Linux x64 Windows x64 -5.5MB - 6.8MB -3.8MB 9% smaller 8% smaller 4% smaller 60.2 โ†’ 54.7 MB 88.5 โ†’ 81.7 MB 93.9 โ†’ 90.1 MB All 12 targets โ€ข average - 6.7 MB โ€ข up to - 11.5 MB on macOS x64

ALT Bun Smaller in Rust. macOS arm64 Linux x64 Windows x64 -5.5MB - 6.8MB -3.8MB 9% smaller 8% smaller 4% smaller 60.2 โ†’ 54.7 MB 88.5 โ†’ 81.7 MB 93.9 โ†’ 90.1 MB All 12 targets โ€ข average - 6.7 MB โ€ข up to - 11.5 MB on macOS x64

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many are saying this
Dean ๅˆฉ่ฟชๆฉ (โš›๏ธ,๐Ÿฑ) | sbpf/acc
@deanmlittle
May 22
it has recently come to my attention that bun is very good and everyone should use it.
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In the next version of Bun TC39 Stage3 proposal `import deferโ€™ lets you lazy load imports
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github.com/oven-sh/bun/pull/โ€ฆ

Implement static `import defer` (TC39 Stage 3) by robobun ยท Pull Request #30975 ยท oven-sh/bun

Implements the static form of the Stage 3 Deferred Module Evaluation proposal: import defer * as ns from "./mod.js"; // mod.js is fetched and linked now, but NOT evaluated. conso...

github.com
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Bun Smaller in Rust. macOS arm64 Linux x64 Windows x64 -5.5MB - 6.8MB -3.8MB 9% smaller 8% smaller 4% smaller 60.2 โ†’ 54.7 MB 88.5 โ†’ 81.7 MB 93.9 โ†’ 90.1 MB All 12 targets โ€ข average - 6.7 MB โ€ข up to - 11.5 MB on macOS x64

ALT Bun Smaller in Rust. macOS arm64 Linux x64 Windows x64 -5.5MB - 6.8MB -3.8MB 9% smaller 8% smaller 4% smaller 60.2 โ†’ 54.7 MB 88.5 โ†’ 81.7 MB 93.9 โ†’ 90.1 MB All 12 targets โ€ข average - 6.7 MB โ€ข up to - 11.5 MB on macOS x64

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Bun retweeted
Sรธren Bramer Schmidt
@sorenbs
May 18
The Bun Rust port has fixed at least one critical memory leak ๐Ÿค˜ github.com/oven-sh/bun/issueโ€ฆ

Bun.S3File.arrayBuffer() retains RSS and reaches OOM in a 1 GiB Linux container despite forced GC ยท...

What version of Bun is running? 1.3.11 What platform is your computer? macOS host: Darwin 24.6.0 arm64 arm, Linux container: Linux 6.17.8-orbstack-00308-g8f9c941121b1 aarch64 unknown What steps can...

github.com
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many such cases
Frank
@lifetime0x
May 18
not sure what is ppl's experience with @bunjavascript canary but in our codebase, memory usage is indeed better.
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Bun retweeted
Jarred Sumner
@jarredsumner
May 18
On the "bundle Three.js 10 times with minification & sourcemaps" benchmark, Bun's Rust port is currently 10% faster than the original
root@hostname ~/r/a/three10x (main)# taskset -c 0-2 hyperfine "bun build ./entry.js --outdir=dist-bun --production --sourcemap=external" "bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external" --warmup=5 Benchmark 1: bun build ./entry.js --outdir=dist-bun --production --sourcemap=external Time (mean ยฑ ฯƒ): 277.4 ms ยฑ 5.5 ms [User: 399.6 ms, System: 191.5 ms] Range (min โ€ฆ max): 268.7 ms โ€ฆ 287.1 ms 10 runs Benchmark 2: bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external Time (mean ยฑ ฯƒ): 314.2 ms ยฑ 7.7 ms [User: 532.9 ms, System: 165.8 ms] Range (min โ€ฆ max): 303.9 ms โ€ฆ 332.5 ms 10 runs Summary bun build ./entry.js --outdir=dist-bun --production --sourcemap=external ran 1.13 ยฑ 0.04 times faster than bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external

ALT root@hostname ~/r/a/three10x (main)# taskset -c 0-2 hyperfine "bun build ./entry.js --outdir=dist-bun --production --sourcemap=external" "bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external" --warmup=5 Benchmark 1: bun build ./entry.js --outdir=dist-bun --production --sourcemap=external Time (mean ยฑ ฯƒ): 277.4 ms ยฑ 5.5 ms [User: 399.6 ms, System: 191.5 ms] Range (min โ€ฆ max): 268.7 ms โ€ฆ 287.1 ms 10 runs Benchmark 2: bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external Time (mean ยฑ ฯƒ): 314.2 ms ยฑ 7.7 ms [User: 532.9 ms, System: 165.8 ms] Range (min โ€ฆ max): 303.9 ms โ€ฆ 332.5 ms 10 runs Summary bun build ./entry.js --outdir=dist-bun --production --sourcemap=external ran 1.13 ยฑ 0.04 times faster than bun-1.3.14 build ./entry.js --outdir=dist-bun --production --sourcemap=external

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Bun v1.3.14 - Fixes 92 issues, addressing 380 ๐Ÿ‘ - `Bun.Image` - builtin image processing - global virtual store in bun install - HTTP/3 Bun.serve() - HTTP/3 & HTTP/2 fetch() - `node:worker_threads` stability fixes - -17 MB on Windows, -7 MB on Linux bun.com/blog/bun-v1.3.14

Bun v1.3.14

Fixes 92 issues (addressing 380 ๐Ÿ‘). Bun.Image โ€” a built-in image processing API, 7x faster warm installs with the isolated linker's global store, experimental HTTP/2 and HTTP/3 clients for fetch(),...

bun.com
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In the next version of Bun Bun gets 17 MB smaller on Windows x64
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github.com/oven-sh/bun/pull/โ€ฆ

Shrink Windows binary: lazy-heap threadlocal PathBuffers /OPT:SAFEICF by robobun ยท Pull Request...

Windows bun.exe is ~15 MB larger than Linux bun and ~40 MB larger than macOS. Section-contribution analysis of the canary PDB shows where it goes: Section Windows Linux Delta Cause .text 60....

github.com
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In the next version of Bun Bun gets 8 MB smaller on Linux x64
97MB Bun v1.3.13 89MB Bun v1.3.14 8 MB smaller(โˆ’8.2%)

ALT 97MB Bun v1.3.13 89MB Bun v1.3.14 8 MB smaller(โˆ’8.2%)

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and that is after adding an HTTP3 server, fetch() HTTP3, fetch HTTP2, Bun.Image (including libjpeg-turbo, libspng, libwebp), lsquic
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