npm vs Bun: Faster JavaScript Installs in CI?
Bun’s install command is famously fast - but npm is the default every package and CI image already assumes.
npm is the standard Node package manager bundled with Node. Bun is an all-in-one JavaScript toolkit whose package manager (bun install) is optimized for speed.
| npm | Bun | |
|---|---|---|
| Install speed | Baseline | Much faster |
| Lockfile | package-lock.json | bun.lock (text) / bun.lockb |
| CI install | npm ci | bun install --frozen-lockfile |
| Ecosystem compatibility | Universal | High, occasional edge cases |
| Bundled with | Node.js | Bun runtime |
In CI
bun install is typically much faster than npm ci, which shaves time off the install step on every run. Bun reads package.json and works with the npm registry, so adopting it for installs only (while still running on Node) is common. npm remains the most compatible choice and needs no extra runtime in the image.
Watch the lockfile
Commit the Bun lockfile and use --frozen-lockfile in CI for reproducibility, the same way you would use npm ci. Some native or postinstall-heavy packages occasionally need a fallback to npm.
The verdict
Want faster installs and you can add Bun to your image: Bun for the install step. Want maximum compatibility with zero new tooling: npm ci. Test your full dependency tree under Bun before committing.