Bun v1.4.1 is a big upgrade to Bun’s bundler. On a 200-route React app over simulated 4G, navigating between routes is 38% faster than Bun v1.4.0, and 10% faster than Vite v8.2.2.
Slide titled “Route navigation on 4G”, subtitle “click → lazy route’s chunks fetched, parsed, and rendered by React · lower is better”. Three horizontal bars: Bun 1.4.0, 1104 ms (dark gray); Vite 8, 757 ms (gray); Bun 1.4.1, 681 ms (pink-to-orange gradient, labeled −38%). Table below with columns Bun 1.4.0 / Vite 8 / Bun 1.4.1: Requests per navigation 108 / 108 / 61; LCP, cold first load 736 ms / 560 ms / 576 ms; JS chunks emitted 918 / 908 / 750; Total JS shipped (gzip) 1.75 MB / 1.67 MB / 1.61 MB. Footnote: 200 lazy routes, 800 components, 30 npm deps, React Compiler on in both, headless Chrome, 170 ms RTT / 9 Mbps, cold cache, median of 7 runs × 12 routes; Bun built with bun build –splitting –min-chunk-size=16384 –react-compiler; Vite 8.2 with @vitejs/plugin-react 6 compiler: true.

ALT Slide titled “Route navigation on 4G”, subtitle “click → lazy route’s chunks fetched, parsed, and rendered by React · lower is better”. Three horizontal bars: Bun 1.4.0, 1104 ms (dark gray); Vite 8, 757 ms (gray); Bun 1.4.1, 681 ms (pink-to-orange gradient, labeled −38%). Table below with columns Bun 1.4.0 / Vite 8 / Bun 1.4.1: Requests per navigation 108 / 108 / 61; LCP, cold first load 736 ms / 560 ms / 576 ms; JS chunks emitted 918 / 908 / 750; Total JS shipped (gzip) 1.75 MB / 1.67 MB / 1.61 MB. Footnote: 200 lazy routes, 800 components, 30 npm deps, React Compiler on in both, headless Chrome, 170 ms RTT / 9 Mbps, cold cache, median of 7 runs × 12 routes; Bun built with bun build –splitting –min-chunk-size=16384 –react-compiler; Vite 8.2 with @vitejs/plugin-react 6 compiler: true.

Sep 2, 2026 · 11:50 AM UTC

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Replying to @bunjavascript
Can we even bundle frontend with bun?
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Yes! bun.com/docs/bundler/html-st…

HTML & static sites | Bun Docs

Build static sites, landing pages, and web applications with Bun's bundler

bun.com
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Replying to @bunjavascript
when is 1.4.1 going to drop? will it take as long as Jared's blogpost?
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Replying to @bunjavascript @jarredsumner
Is it out yet???
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Replying to @bunjavascript
38% on a 200-route app over 4G is kinda nuts
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Replying to @bunjavascript @jarredsumner
Even faster than Vite? Goddamn
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Replying to @bunjavascript
ok 38% is actually a huge jump. Bun is getting seriously fast.
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Replying to @bunjavascript @cirospaciari
Faster than @vite_js you say🤔👀
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Replying to @bunjavascript @jarredsumner
Wen solidjs
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Replying to @bunjavascript
The 38% is nice, but the more useful number is 108 → 61 requests. Total gzipped JS only falls 1.75 → 1.61 MB (~8%), yet route latency falls 1104 → 681 ms on 170 ms RTT. That’s a chunk-graph result. Measure request topology per route, not bundle size alone.
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Replying to @bunjavascript
any ETA?
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Replying to @bunjavascript
I was still blaming 4G for slow route hops after a bundler bump. route-nav.md now: measure the same 200-route app before/after. 38% faster is a number I feel in the click, not a changelog line.
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Replying to @bunjavascript
Hey, plz resume posting on Bluesky :>
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Replying to @bunjavascript
fuck and give me 1.4.1
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Replying to @bunjavascript
🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀🦀
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Replying to @bunjavascript
@evanyou 👀
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Replying to @bunjavascript
🚀
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Replying to @bunjavascript
I will try.
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