Bun 1.4 Beats Deno and Node.js in Cold‑Start Benchmarks Before Official Release

Bun released a new cold‑start benchmark using an identical hello‑world file, the same hardware, and a single test round.

The measurements show Bun 1.4 starting in 4.8 ms, Deno 2.9.3 canary at 14.9 ms, and Node.js 26.5.0 at 22.0 ms.

According to Bun’s own algorithm, this makes Bun about 4.5 times faster than Node.js and 3.1 times faster than Deno.

Bun 1.4 is still unreleased; it follows a recent rewrite that moved most low‑level code from Zig to Rust. The previous stable release, 1.3.14 (the last Zig version), had a cold‑start time that once regressed to 19.3 ms, while 1.4 not only fixed that regression but also improved the prior best of 7.1 ms to 4.8 ms, roughly a 1.5× gain.

Community comments noted the curiosity about a 4.7 ms figure, with one user guessing the difference stems from the build being based on Opus 4.8 rather than 4.7.

The author cautions that the test only measures Bun’s strength in hello‑world cold starts and does not reflect throughput, compatibility, or real‑world workloads; Node.js’s extensive ecosystem cannot be dismissed by a single bar chart.

Recent news about the open‑source competitor OpenCode 2.0 removing Bun‑specific APIs and shifting core services to Node.js is referenced, highlighting that benchmark numbers are only one factor in project selection, which ultimately depends on ecosystem and architecture considerations.

When Bun 1.4 becomes generally available, developers are advised to run their own benchmarks on actual projects before making migration decisions.

Reference Link

https://mp.weixin.qq.com/s/JgbtH06v8wMu3hzksg-1Mg