Bun

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What is Bun?

Bun is an all-in-one toolkit for JavaScript and TypeScript apps. It ships as a single executable called bun.

At its core is the Bun runtime, a fast JavaScript runtime designed as a drop-in replacement for Node.js. It's written in Rust and powered by JavaScriptCore under the hood, dramatically reducing startup times and memory usage.

bun run index.tsx             # TS and JSX supported out-of-the-box

The bun command-line tool also implements a test runner, script runner, and Node.js-compatible package manager. Instead of 1,000 node_modules for development, you only need bun. Bun's built-in tools are significantly faster than existing options and usable in existing Node.js projects with little to no changes.

bun test                      # run tests
bun run start                 # run the `start` script in `package.json`
bun install <pkg>             # install a package
bunx cowsay 'Hello, world!'   # execute a package

Install

Bun supports Linux (x64 & arm64), macOS (x64 & Apple Silicon), and Windows (x64 & arm64).

Linux users — Kernel version 5.6 or higher is strongly recommended, but the minimum is 5.1.

x64 users — if you see "illegal instruction" or similar errors, check our CPU requirements

# with install script (recommended)
curl -fsSL https://bun.com/install | bash

# on windows
powershell -c "irm bun.sh/install.ps1 | iex"

# with npm
npm install -g bun

# with Homebrew
brew tap oven-sh/bun
brew install bun

# with Docker
docker pull oven/bun
docker run --rm --init --ulimit memlock=-1:-1 oven/bun

Upgrade

To upgrade to the latest version of Bun, run:

bun upgrade

Bun automatically releases a canary build on every commit to main. To upgrade to the latest canary build, run:

bun upgrade --canary

View canary build

Quick links

• Intro

  • What is Bun?
  • Installation
  • Quickstart
  • TypeScript
  • TypeScript 6

• Templating

  • bun init
  • bun create

• Runtime

  • bun run
  • File types (Loaders)
  • JSX
  • Environment variables
  • Bun APIs
  • Web APIs
  • Node.js compatibility
  • Plugins
  • Watch mode / Hot Reloading
  • Module resolution

Guides

• Deployment

  • Deploy to Vercel
  • Deploy to Railway
  • Deploy to Render
  • Deploy to AWS Lambda
  • Deploy to DigitalOcean
  • Deploy to Google Cloud Run

• Binary

  • Convert a Blob to a string
  • Convert a Buffer to a blob
  • Convert a Blob to a DataView
  • Convert a Buffer to a string
  • Convert a Blob to a ReadableStream
  • Convert a Blob to a Uint8Array
  • Convert a DataView to a string
  • Convert a Uint8Array to a Blob
  • Convert a Blob to an ArrayBuffer
  • Convert an ArrayBuffer to a Blob

Contributing

Refer to the Project > Contributing guide to start contributing to Bun.

License

Refer to the Project > License page for information about Bun's licensing.