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Bun {bot}
@bunjsbot.eurosky.social
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Unofficial mirror account of https://x.com/bunjavascript from Twitter

Bun is a fast, all-in-one toolkit for installing, bundling, running and testing JavaScript & TypeScript. To install: `npm i -g bun`
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bunjsbot.eurosky.social
In the next version of Bun

We fixed a GC retention cycle that made Next.js App Router SSR leak memory when a page called fetch() https://twitter.com/bunjavascript/status/2083723523667972153
Next.js 16 · App Router · next start. The SSR memory leak is gone in Bun v1.4.” Subtitle: “4,000 server-rendered pages: Bun v1.4 settles at 238 MB, under Node’s 410 MB. Bun v1.3.14 climbed to 1,983 MB and kept going.” A line chart of server memory (RSS) against requests served, 0 to 4,000, then a dashed tail to the value after 5 seconds idle. Bun v1.3.14 rises steadily to a 1,983 MB peak and settles at 1,901 MB; Node v26.5 flattens around 400 MB and settles at 410 MB; Bun v1.4 stays flat near 300–350 MB and settles at 238 MB. Footer: stock create-next-app (Next 16.2.3, React 19.2) with the bug report’s page — a React.cache-wrapped fetch(…, { cache: “no-store” }) in a dynamic route; 4,000 unique URLs at 50 concurrent; server RSS sampled from /proc every 200 requests; product API is a separate Node process; Linux x64; bun 1.4.0-canary f91d5c95c, bun 1.3.14, node 26.5.0.
August 2, 2026 at 4:58 AM
bunjsbot.eurosky.social
In the next version of Bun

Saving streaming file uploads to disk via Bun.write uses 35x less memory compared to Bun v1.3.14 https://twitter.com/bunjavascript/status/2083708247354245464
Benchmark card titled “Saving 5,000 uploads to disk · 2 MB each — same Hono app, three runtimes.” Subtitle: “Bun v1.4 uses 35× less memory than v1.3.14 and takes uploads at 1.65× Node’s requests per second.” Horizontal bar chart of peak memory (max RSS of the server process, shorter is better): Bun v1.4 316 MB, Bun v1.3.14 11,142 MB (bar fills the track), Node v26.5 213 MB. Smaller figures below: requests per second — Bun v1.4 999, Bun v1.3.14 552, Node 604; CPU time — Bun v1.4 16.3 s, Bun v1.3.14 20.8 s, Node 19.5 s. Route under test: app.post(”/upload”, async (c) => { await Bun.write(path, c.req.raw); return c.text(“ok”) }), with a note that Node saves it with await pipeline(Readable.fromWeb(c.req.raw.body), createWriteStream(path)). Footer: oha -c 100 -n 5000 -m POST -D 2mb.bin, same Hono 4.12 app on each runtime, each saving the body its idiomatic way, Linux x64, GNU time -v, median of 5 runs; bun 1.4.0-canary f91d5c95c, bun 1.3.14, node 26.5.0.
August 2, 2026 at 4:58 AM
bunjsbot.eurosky.social
In the next version of Bun

Proxying file uploads uses 10x less memory than in v1.3.14 https://twitter.com/bunjavascript/status/2083704350472573224
Benchmark card titled “Relaying 300 uploads to storage · 20 MB each — same Hono app, three runtimes.” Subtitle: “Bun v1.4 matches Node’s memory at a third of the CPU — v1.3.14 needed 11× more RAM.” Horizontal bar chart of peak memory (max RSS of the server process, shorter is better): Bun v1.4 205 MB, Bun v1.3.14 2,259 MB (bar fills the track), Node v26.5 203 MB. Smaller figures below: CPU time — Bun v1.4 5.0 s, Bun v1.3.14 8.0 s, Node 13.9 s; wall clock — 31.5 s, 31.5 s, 31.6 s (storage sets the pace). Route under test: app.post(”/relay”, (c) => fetch(bucketUrl, { method: “PUT”, body: c.req.raw.body, duplex: “half” })). Footer: oha -c 100 -n 300 -m POST -D 20mb.bin, same Hono 4.12 app on each runtime, storage endpoint capped at 200 MB/s with tc, Linux x64, GNU time -v, median of 5 runs; bun 1.4.0-canary f91d5c95c, bun 1.3.14, node 26.5.0.
August 2, 2026 at 4:58 AM
bunjsbot.eurosky.social
In the next version of Bun

Several bugs involving backpressure propagation have been fixed https://twitter.com/bunjavascript/status/2083702383172075745
Benchmark card titled “Proxying 2,000 downloads · 2 MB each — same Hono app, three runtimes.” Subtitle: “Bun v1.4 holds half the memory of Node while serving 2× the requests per second.” A horizontal bar chart of peak memory (max RSS of the server process, shorter is better): Bun v1.4 171 MB, Bun v1.3.14 245 MB, Node v26.5 326 MB. Below, smaller figures: requests per second — Bun v1.4 868, Bun v1.3.14 948, Node 443; CPU time — Bun v1.4 3.9 s, Bun v1.3.14 3.6 s, Node 6.3 s. The route under test is one line: app.get(”/proxy”, (c) => fetch(originUrl)). Footer: oha -c 100 -n 2000, same Hono 4.12 app on each runtime, origin serves at line rate, Linux x64, GNU time -v for max RSS and CPU, median of 5 runs; bun 1.4.0-canary f91d5c95c, bun 1.3.14, node 26.5.0.
August 2, 2026 at 4:58 AM
bunjsbot.eurosky.social
In the next version of Bun

Bun.serve can serve a whole folder https://twitter.com/bunjavascript/status/2082489775001616446
Image from Twitter
August 2, 2026 at 4:57 AM
bunjsbot.eurosky.social
https://twitter.com/bunjavascript/status/2082298681223680002
Bun v1.4 fixes over 3,000 GitHub issues since Bun v1.3 3,064 3,000 2,069 A +70% fixed 2,000 1,792 1,000 Bun v1.2 This cycle Bun fixes 85 öven-sh/bün: GitHüb issues closed as completed, per release cycle as of July 2026" Bun v1.3 issues for every 100 opened up from 49 Bun v1.4 coming next week
August 2, 2026 at 4:57 AM
bunjsbot.eurosky.social
In the next version of Bun

bun:ffi gets up to 3x faster https://twitter.com/bunjavascript/status/2081172248967397417
BUN:FFI • REWRITTEN AS ENGINE-NATIVE FFI IN JAVASCRIPTCORE up to 3× faster ffi Symbols & callbacks are engine cells • hot call sites JIT to a bare call; ret • 70× less memory/ symbol 3.0x 3.3x O bun TinyccO bun •JSC-native 2.3x 1.4x TINYCC = 1x noop call 2.27 ns → 763 ps new CString( 99.5 → 30 ns yoga layout x1k opentui benchmark speedup vs previous TinyCC-based bun:ffi macOS arm64 • opentui: unmodified 347-symbol app scrollbox 10k opentui benchmark
August 2, 2026 at 4:57 AM
bunjsbot.eurosky.social
Closed 911 issues as completed in the last 24 hrs.

Many fixed in recent PRs. Some fixed long ago. https://twitter.com/bunjavascript/status/2080882189663907859
Closed | 911 https://github.com/oven-sh/bun/issues?q=is%3Aissue%20state%3Aclosed%20closed%3A%3E2026-07-23%20reason%3Acompleted
August 2, 2026 at 4:56 AM
bunjsbot.eurosky.social
Bun v1.4 starts faster https://twitter.com/bunjavascript/status/2080440103399494100
Bun v1.4 starts faster than every other Bun. 4.8ms MS 20 COLD START • HELLO WORLD 1.3.14 •19.3ms startup regression — fixed in v1.4 10 fastest before v1.4 - 7.1ms V1.0 V1.1 V1.2 v1.3 4x faster than 1.3.14 • 1.5x faster than any Bun before it console. log (123) • hyperfine, 400 runs, pinned core • Linux x64, AMD EPYC 9R14 • v1.4 = main @ b39a2704 v1.4
August 2, 2026 at 4:56 AM
bunjsbot.eurosky.social
Bun v1.4 will be our biggest jump in Node.js compatibility since Bun v1.0 https://twitter.com/bunjavascript/status/2079863261630267773
Line chart titled "Bun's Node.js test suite progress", subtitled "Official Node.js test suite files run on every commit". The line starts at 1,378 test files at Bun v1.2.0 (January 2025), climbs through the 1.2 series to 2,250 at v1.3.14, holds flat across the 1.3 releases, then spikes to 3,188 files on main today (July 2026). A dashed target line at 3,693 reads "The bar to ship Bun v1.4: 3,693", with "505 to go" marking the gap between main and the target.
August 2, 2026 at 4:55 AM
bunjsbot.eurosky.social
In the next version of Bun

Improved timer accuracy on Windows makes `Bun.sleep` faster https://twitter.com/bunjavascript/status/2079346398647177256
bun index.js - 1.55s bun-1.4 index.js - 142ms
August 2, 2026 at 4:55 AM
bunjsbot.eurosky.social
In the next version of Bun

94% of node:http tests from the Node.js v26 test suite pass, thanks to @cirospaciari https://twitter.com/bunjavascript/status/2078024909452919252
Image from Twitter
August 2, 2026 at 4:55 AM
bunjsbot.eurosky.social
In the next version of Bun

node:sqlite is fully implemented and passes 100% of Node.js’ test suite https://twitter.com/bunjavascript/status/2078027352412680326
Image from Twitter
August 2, 2026 at 4:54 AM
bunjsbot.eurosky.social
the next version of Bun

93% of node:http2 tests from the Node.js v26 test suite pass, thanks to @cirospaciari https://twitter.com/bunjavascript/status/2078026179832168556
Image from Twitter
August 2, 2026 at 4:54 AM
bunjsbot.eurosky.social
In the next version of Bun

Idle CPU usage drops by 5x https://twitter.com/bunjavascript/status/2076926338951479669
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.
August 2, 2026 at 4:54 AM
bunjsbot.eurosky.social
In the next version of Bun

Bun uses up to 32% less memory https://twitter.com/bunjavascript/status/2076912657400221811
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)
August 2, 2026 at 4:54 AM
bunjsbot.eurosky.social
many are saying this

QT: https://twitter.com/i/status/2070226360497512601
July 10, 2026 at 4:23 AM
bunjsbot.eurosky.social
monthly downloads https://twitter.com/bunjavascript/status/2069683422096982168
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).
July 10, 2026 at 4:23 AM
bunjsbot.eurosky.social
In the next version of Bun

The `"compress"` option in `fetch` compresses the request body for you https://twitter.com/bunjavascript/status/2069610810595545449
Bun await fetch(url, { method: "POST", body, compress: "gzip",→ sets Content-Encoding: gzip });
July 10, 2026 at 4:23 AM
bunjsbot.eurosky.social
In the next version of Bun

`process` emits a "memoryPressure" event when the system runs low on memory (thanks @codebytere!) https://twitter.com/bunjavascript/status/2069607247668510914
Bun · react to system memory pressure // level: "warning" | "critical" process.on("memoryPressure", (level) => { if (level === "critical") cache.clear(); });
July 10, 2026 at 4:23 AM
bunjsbot.eurosky.social
https://www.prisma.io/blog/bun-rust-rewrite-prisma-compute
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.
www.prisma.io
June 14, 2026 at 7:19 AM
bunjsbot.eurosky.social
Rust
Image from Twitter
June 12, 2026 at 2:20 PM
bunjsbot.eurosky.social
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") 4.8× 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 (5.2× faster) mitata • Apple M4 Max • Node.js 25.2.1 552.2 553.5 us lower is better
June 12, 2026 at 2:20 PM
bunjsbot.eurosky.social
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") 41× 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 • mitata • Apple M4 Max 3,320 us lower is better
June 12, 2026 at 2:20 PM
bunjsbot.eurosky.social
In the next version of Bun

Bun.stringWidth() 处理中文、日文、韩文字符的速度提升了 7~56 倍

Bun.stringWidth() が中国語・日本語・韓国語の文字で 7〜56 倍高速化されました

Bun.stringWidth()가 중국어·일본어·한국어 문자에서 7~56배 빨라졌습니다
❯ bun string-width.mjs clk: ~3.82 GHz cpu: Apple M4 Max runtime: bun 1.4.0 (arm64-darwin) benchmark avg (min … max) p75 p99 (min … top 1%) ------------------------------------------- ------------------------------- Bun.stringWidth - cjk 7 19.17 ns/iter 19.87 ns █ (17.12 ns … 26.40 ns) 21.05 ns ▁▁▁▁▂▁█▃█▁▂█▄▂▆▅▂▅▂▁▁ Bun.stringWidth - cjk 70 30.67 ns/iter 31.01 ns █ ▃ (26.32 ns … 58.46 ns) 33.44 ns ▁▁▁▁▁▁▁▁▁▂▆█▆█▄▅▁▂▁▁▁ Bun.stringWidth - cjk 700 243.57 ns/iter 246.04 ns █ (216.38 ns … 256.17 ns) 249.29 ns ▁▁▁▁▁▁▁▁▁▁▁▁▂▁▁▂▄▂█▂▁ Bun.stringWidth - cjk 7,000 2.42 µs/iter 2.43 µs █ (2.38 µs … 2.44 µs) 2.43 µs ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁█▄ Bun.stringWidth - cjk 35,000 12.12 µs/iter 12.13 µs █ (12.08 µs … 12.16 µs) 12.14 µs █▁▁▁▁▁▁▁▁▁▁▁██▁██▁▁██ bun/bench/snippets on  main [$!
June 12, 2026 at 2:20 PM