oven-sh/setup-bun

Download, install, and add Bun to the PATH so later steps can run bun commands.

Official actionCategory: Language & Toolchain SetupLatest v2View on GitHub

What it does

oven-sh/setup-bun downloads and installs Bun so later steps can run bun install, bun test, or bunx.

The version can come from the bun-version input, a version file like .bun-version or package.json, or default to the latest release. The Bun executable is cached between runs unless disabled.

Usage

workflow (.yml)

steps:
  - uses: actions/checkout@v4
  - uses: oven-sh/setup-bun@v2
    with:
      bun-version: latest
  - run: bun install
  - run: bun test

Inputs

Input	Description	Default	Required
`bun-version`	Version of Bun to install, e.g. "latest", "canary", "1.0.0", "1.0.x", or a commit SHA.	-	No
`bun-version-file`	File to read the Bun version from, e.g. package.json, .bun-version, .tool-versions.	-	No
`bun-download-url`	Override the download URL. Skips version resolution and the AVX2 support check.	-	No
`registries`	Package registries with authentication support, including scoped registries with tokens.	-	No
`no-cache`	Disable caching of the Bun executable.	`false`	No

Outputs

Output	Description
`bun-version`	The version of Bun that was installed.
`bun-path`	The path to the Bun executable.
`cache-hit`	Whether the Bun executable came from the cache.

Notes

Resolving wildcard or range versions queries the GitHub API for tags; the default token input covers this on github.com, and a PAT helps on GHES if you hit rate limits.

Common errors

Version resolution can fail with a GitHub API rate-limit error when resolving wildcard or range versions on busy runners; pass a token or pin an exact bun-version.
Bun crashing immediately after install on old or exotic CPUs is usually missing AVX2 support; bun-download-url skips the AVX2 check, so only override it if you know the target supports the build.

Security and pinning

Pin the action to a commit SHA and pin bun-version to an exact version for reproducible builds.
Pass registry tokens in the registries input from secrets, never inline in the workflow file.

Alternatives and related

actions/setup-nodeInstall a specific Node.js version and cache your npm, yarn, or pnpm dependencies. pnpm/action-setupInstall the pnpm package manager, so setup-node can cache the pnpm store. actions/cacheCache any files between workflow runs, keyed on a hash of your lockfiles.

Frequently asked questions

How do I keep CI on the same Bun version as my repo?

Commit a .bun-version file (or set the version in package.json) and point bun-version-file at it, so CI and local dev resolve the same version.