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Bun
4,004 posts
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Bun
@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
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80.1K
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  • 已置顶
    user avatar
    Bun
    @bunjavascript
    2025年12月2日
    Bun is joining Anthropic!
    Bun is joining Anthropic
    From bun.com
    4M
  • user avatar
    Bun
    @bunjavascript
    7月14日
    In the next version of Bun Idle CPU usage drops by 5x
    Bun 1.4
idle · 120 s · n=3
5.4× lower idle CPU usage
Parked on setTimeout(fn, 10min): 253,312 instructions/sec → 47,078.

1.3.14 — scavenger polls ~10 Hz
0.067%
1.4 — nothing to poll
~ 0.000%
instructions/sec, idle	253,312 → 47,078	−81%
idle Bun.serve, CPU	0.075% → 0.008%	−89%
madvise calls/sec	1.2 → 0	−100%
libpas polled its scavenger 10× a second, forever. 0.000% is rounded, not zero. Thread count unchanged.
    79.6K
  • user avatar
    Bun
    @bunjavascript
    7月14日
    In the next version of Bun Bun uses up to 32% less memory
    Bun 1.4
Up to 32% lower memory usage
Peak RSS vs 1.3.14. Linux x64 on an EC2 instance.

HTTP servers · MB
next start
381 → 256
−32.9%
fastify
208 → 148
−29.2%
node:http server
158 → 113
−28.3%
vite dev server
307 → 227
−26.2%
elysia
79 → 59
−25.5%
express
161 → 129
−19.7%
Bun.serve static
39 → 34
−14.3%
Bun.serve fetch
47 → 42
−11.4%
vite preview
177 → 158
−10.7%
Build · lint · format · tsc · MB
create-vite lint
374 → 216
−42.3%
create-vue lint
350 → 246
−29.8%
create-vite tsc
499 → 366
−26.7%
create-vite tsc+build
497 → 365
−26.6%
create-vue format
160 → 121
−24.7%
create-vue build
383 → 310
−19.0%
create-next lint
400 → 326
−18.5%
elysia build
851 → 703
−17.4%
create-next build
993 → 926
−6.7%
bun install · cold cache · MB
create-next
272 → 140
−48.6%
create-vue
148 → 95
−35.5%
elysia
135 → 99
−26.7%
create-vite
82 → 62
−24.4%
fastify
46 → 36
−21.7%
express
26 → 21
−17.4%
also: --frozen-lockfile −18…−28% · startup −5…−8% · throughput flat to +24% rps (next start)
    113K
  • Bun reposted
    user avatar
    Yusuke Wada
    @yusukebe
    7月13日
    ってかBunの1.4めちゃくちゃ速い!2倍以上速いケースもある
    20K
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    7月8日
    Rewriting Bun in Rust
    Rewriting Bun in Rust
    From bun.com
    4M
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    7月5日
    In the next version of Bun Bun uses 8 MB less memory on Linux at start
    Max RSS at startup  ·  Linux x64

Bun 1.4 uses 8 MB less memory on Linux
−8.1 MB
20.3MB(rss)
28.4MB(rss)
40MB(rss)
47.2MB(rss)
bun 1.4
bun -e 123

bun 1.3.14
bun-1.3.14 -e 123

node
node -e 123

deno
deno eval 123

Every runtime given the same program: 123
    136K
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    7月4日
    rust rewrite blog post Monday Bun v1.4 hopefully Tuesday (video still editing)
    91.1K
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    7月4日
    In the next version of Bun Web Streams get faster, use less memory, and pass 100% of relevant Web Platform Tests
    bun · web streams, rewritten in native
Web Streams in Bun get faster
bun 1.4.0
bun 1.3.14
node 26
deno 2.9
million 64 KiB chunks/sec · higher is better
reader.read() loop
1.85M
1.20M
0.87M
0.69M
2.13×
for await…of
1.41M
0.93M
0.58M
0.43M
3.28×
pipeTo()
0.64M
0.53M
0.41M
0.38M
1.68×
pipeThrough()
0.47M
0.27M
0.22M
0.20M
2.14×
tee() + drain both
0.77M
0.42M
0.36M
0.19M
2.14×
vs bun 1.3.14 · 32 MiB per pass, best of 5, median of 3 isolated processes, release builds · node v26.3.0, deno 2.9.1 (canary) · linux x64 · peak RSS 38–41 MB vs 44–54 (bun 1.3.14), 50–57 (node), 57–63 (deno)
    54.6K
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    6月30日
    In the next version of Bun bun install & bun's bundler get a new SIMD-optimized JSON parser In ideal conditions: package installs get up to 40% faster & peak memory usage drops by 2x
    ❯ NPM_CONFIG_REGISTRY=http://127.0.0.1:4873/ hyperfine "bun install --ignore-scripts --no-cache" "bun-1.3.14 install --ignore-scripts --no-cache" --warmup=2 --prepare="rm -f bun.lock"
Benchmark 1: bun install --ignore-scripts --no-cache
  Time (mean ± σ):     221.4 ms ±   5.9 ms    [User: 549.8 ms, System: 136.6 ms]
  Range (min … max):   212.4 ms … 232.3 ms    11 runs

Benchmark 2: bun-1.3.14 install --ignore-scripts --no-cache
  Time (mean ± σ):     328.1 ms ±   6.5 ms    [User: 1135.1 ms, System: 202.7 ms]
  Range (min … max):   319.8 ms … 335.5 ms    10 runs

Summary
  bun install --ignore-scripts --no-cache ran
    1.48 ± 0.05 times faster than bun-1.3.14 install --ignore-scripts --no-cache
    60.1K
  • user avatar
    Bun
    @bunjavascript
    6月25日
    many are saying this
    user avatar
    Reyansh Bahl
    @reyanshbahl
    6月25日
    Replying to @jarredsumner @saltjsx and @bunjavascript
    bun is so fast the anti-cheat software had to stop it
    22K
  • Bun reposted
    user avatar
    Jarred Sumner
    Bun
    @jarredsumner
    6月24日
    Bun v1.4 ships July 7th
    74.5K
  • user avatar
    Bun
    @bunjavascript
    6月24日
    monthly downloads
    Bun monthly downloads (GitHub + npm + Docker + upgrades), Sep 2025 – May 2026: 5.1M → 6.3M → 6.8M → 7.4M → 9.1M → 11.0M → 12.5M → 16.5M → 19.6M. Markers at Bun 1.3 (Oct 10 2025) and Anthropic acquisition (Dec 2 2025).
    36K
  • user avatar
    Bun
    @bunjavascript
    6月24日
    In the next version of Bun The `"compress"` option in `fetch` compresses the request body for you
    Bun
await fetch(url, {
  method: "POST",
  body,
  compress: "gzip",→ sets Content-Encoding: gzip
});
    43.9K
  • user avatar
    Bun
    @bunjavascript
    6月24日
    In the next version of Bun `process` emits a "memoryPressure" event when the system runs low on memory (thanks @codebytere!)
    Bun · react to system memory pressure
// level: "warning" | "critical"
process.on("memoryPressure", (level) => {
  if (level === "critical") cache.clear();
});
    44.3K