Bun
What is Bun?
Bun is under active development. Use it to speed up your development workflows or run simpler production code in resource-constrained environments like serverless functions. We're working on more complete Node.js compatibility and integration with existing frameworks. Join the Discord and watch the GitHub repository to keep tabs on future releases.
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 Zig 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-boxThe 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 packageInstall
Bun supports Linux (x64 & arm64), macOS (x64 & Apple Silicon) and Windows (x64).
Linux users — Kernel version 5.6 or higher is strongly recommended, but the minimum is 5.1.
# with install script (recommended)
curl -fsSL https://bun.sh/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/bunUpgrade
To upgrade to the latest version of Bun, run:
bun upgradeBun automatically releases a canary build on every commit to main. To upgrade to the latest canary build, run:
bun upgrade --canaryQuick links
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Intro
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Templating
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Runtime
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Package manager
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Bundler
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Test runner
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Package runner
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API
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Project
Guides
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Binary
- Convert a Blob to a DataView
- Convert a Blob to a ReadableStream
- Convert a Blob to a string
- Convert a Blob to a Uint8Array
- Convert a Blob to an ArrayBuffer
- Convert a Buffer to a blob
- Convert a Buffer to a ReadableStream
- Convert a Buffer to a string
- Convert a Buffer to a Uint8Array
- Convert a Buffer to an ArrayBuffer
- Convert a DataView to a string
- Convert a Uint8Array to a Blob
- Convert a Uint8Array to a Buffer
- Convert a Uint8Array to a DataView
- Convert a Uint8Array to a ReadableStream
- Convert a Uint8Array to a string
- Convert a Uint8Array to an ArrayBuffer
- Convert an ArrayBuffer to a Blob
- Convert an ArrayBuffer to a Buffer
- Convert an ArrayBuffer to a string
- Convert an ArrayBuffer to a Uint8Array
- Convert an ArrayBuffer to an array of numbers
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Ecosystem
- Build a frontend using Vite and Bun
- Build an app with Astro and Bun
- Build an app with Next.js and Bun
- Build an app with Nuxt and Bun
- Build an app with Qwik and Bun
- Build an app with Remix and Bun
- Build an app with SolidStart and Bun
- Build an app with SvelteKit and Bun
- Build an HTTP server using Elysia and Bun
- Build an HTTP server using Express and Bun
- Build an HTTP server using Hono and Bun
- Build an HTTP server using StricJS and Bun
- Containerize a Bun application with Docker
- Create a Discord bot
- Read and write data to MongoDB using Mongoose and Bun
- Run Bun as a daemon with PM2
- Run Bun as a daemon with systemd
- Server-side render (SSR) a React component
- Use Drizzle ORM with Bun
- Use EdgeDB with Bun
- Use Neon's Serverless Postgres with Bun
- Use Prisma with Bun
- Use React and JSX
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HTTP
- Common HTTP server usage
- Configure TLS on an HTTP server
- fetch with unix domain sockets in Bun
- Hot reload an HTTP server
- Proxy HTTP requests using fetch()
- Send an HTTP request using fetch
- Start a cluster of HTTP servers
- Stream a file as an HTTP Response
- Streaming HTTP Server with Async Iterators
- Streaming HTTP Server with Node.js Streams
- Upload files via HTTP using FormData
- Write a simple HTTP server
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Install
- Add a dependency
- Add a development dependency
- Add a Git dependency
- Add a peer dependency
- Add a tarball dependency
- Add a trusted dependency
- Add an optional dependency
- Configure a private registry for an organization scope with bun install
- Configure git to diff Bun's lockb lockfile
- Configuring a monorepo using workspaces
- Generate a human-readable lockfile
- Install a package under a different name
- Install dependencies with Bun in GitHub Actions
- Override the default npm registry for bun install
- Using bun install with an Azure Artifacts npm registry
- Using bun install with Artifactory
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Process
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Read file
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Runtime
- Debugging Bun with the VS Code extension
- Debugging Bun with the web debugger
- Define and replace static globals & constants
- Import a JSON file
- Import a TOML file
- Import HTML file as text
- Install and run Bun in GitHub Actions
- Install TypeScript declarations for Bun
- Re-map import paths
- Read environment variables
- Run a Shell Command
- Set a time zone in Bun
- Set environment variables
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Streams
- Convert a Node.js Readable to a Blob
- Convert a Node.js Readable to a string
- Convert a Node.js Readable to an ArrayBuffer
- Convert a Node.js Readable to JSON
- Convert a ReadableStream to a Blob
- Convert a ReadableStream to a Buffer
- Convert a ReadableStream to a string
- Convert a ReadableStream to a Uint8Array
- Convert a ReadableStream to an array of chunks
- Convert a ReadableStream to an ArrayBuffer
- Convert a ReadableStream to JSON
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Test
- Bail early with the Bun test runner
- Generate code coverage reports with the Bun test runner
- Mark a test as a "todo" with the Bun test runner
- Migrate from Jest to Bun's test runner
- Mock functions in
bun test - Re-run tests multiple times with the Bun test runner
- Run tests in watch mode with Bun
- Run your tests with the Bun test runner
- Set a code coverage threshold with the Bun test runner
- Set a per-test timeout with the Bun test runner
- Set the system time in Bun's test runner
- Skip tests with the Bun test runner
- Spy on methods in
bun test - Update snapshots in
bun test - Use snapshot testing in
bun test - Write browser DOM tests with Bun and happy-dom
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Util
- Check if the current file is the entrypoint
- Check if two objects are deeply equal
- Compress and decompress data with DEFLATE
- Compress and decompress data with gzip
- Convert a file URL to an absolute path
- Convert an absolute path to a file URL
- Detect when code is executed with Bun
- Encode and decode base64 strings
- Escape an HTML string
- Get the absolute path of the current file
- Get the absolute path to the current entrypoint
- Get the current Bun version
- Get the directory of the current file
- Get the file name of the current file
- Get the path to an executable bin file
- Hash a password
- Sleep for a fixed number of milliseconds
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WebSocket
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Write file
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.