Bun
### [Read the docs →](https://bun.com/docs)
## 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 Zig and powered by JavaScriptCore under the hood, dramatically reducing startup times and memory usage.
```bash
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.
```bash
bun test # run tests
bun run start # run the `start` script in `package.json`
bun install # 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](https://bun.com/docs/installation#cpu-requirements-and-baseline-builds)
```sh
# 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:
```sh
bun upgrade
```
Bun automatically releases a canary build on every commit to `main`. To upgrade to the latest canary build, run:
```sh
bun upgrade --canary
```
[View canary build](https://github.com/oven-sh/bun/releases/tag/canary)
## Quick links
- Intro
- [What is Bun?](https://bun.com/docs/index)
- [Installation](https://bun.com/docs/installation)
- [Quickstart](https://bun.com/docs/quickstart)
- [TypeScript](https://bun.com/docs/typescript)
- Templating
- [`bun init`](https://bun.com/docs/cli/init)
- [`bun create`](https://bun.com/docs/cli/bun-create)
- CLI
- [`bun upgrade`](https://bun.com/docs/cli/bun-upgrade)
- Runtime
- [`bun run`](https://bun.com/docs/cli/run)
- [File types (Loaders)](https://bun.com/docs/runtime/loaders)
- [TypeScript](https://bun.com/docs/runtime/typescript)
- [JSX](https://bun.com/docs/runtime/jsx)
- [Environment variables](https://bun.com/docs/runtime/environment-variables)
- [Bun APIs](https://bun.com/docs/runtime/bun-apis)
- [Web APIs](https://bun.com/docs/runtime/web-apis)
- [Node.js compatibility](https://bun.com/docs/runtime/nodejs-compat)
- [Single-file executable](https://bun.com/docs/bundler/executables)
- [Plugins](https://bun.com/docs/runtime/plugins)
- [Watch mode / Hot Reloading](https://bun.com/docs/runtime/watch-mode)
- [Module resolution](https://bun.com/docs/runtime/modules)
- [Auto-install](https://bun.com/docs/runtime/autoimport)
- [bunfig.toml](https://bun.com/docs/runtime/bunfig)
- [Debugger](https://bun.com/docs/runtime/debugger)
- [$ Shell](https://bun.com/docs/runtime/shell)
- Package manager
- [`bun install`](https://bun.com/docs/cli/install)
- [`bun add`](https://bun.com/docs/cli/add)
- [`bun remove`](https://bun.com/docs/cli/remove)
- [`bun update`](https://bun.com/docs/cli/update)
- [`bun link`](https://bun.com/docs/cli/link)
- [`bun unlink`](https://bun.com/docs/cli/unlink)
- [`bun pm`](https://bun.com/docs/cli/pm)
- [`bun outdated`](https://bun.com/docs/cli/outdated)
- [`bun publish`](https://bun.com/docs/cli/publish)
- [`bun patch`](https://bun.com/docs/install/patch)
- [`bun patch-commit`](https://bun.com/docs/cli/patch-commit)
- [Global cache](https://bun.com/docs/install/cache)
- [Workspaces](https://bun.com/docs/install/workspaces)
- [Lifecycle scripts](https://bun.com/docs/install/lifecycle)
- [Filter](https://bun.com/docs/cli/filter)
- [Lockfile](https://bun.com/docs/install/lockfile)
- [Scopes and registries](https://bun.com/docs/install/registries)
- [Overrides and resolutions](https://bun.com/docs/install/overrides)
- [`.npmrc`](https://bun.com/docs/install/npmrc)
- Bundler
- [`Bun.build`](https://bun.com/docs/bundler)
- [Loaders](https://bun.com/docs/bundler/loaders)
- [Plugins](https://bun.com/docs/bundler/plugins)
- [Macros](https://bun.com/docs/bundler/macros)
- [vs esbuild](https://bun.com/docs/bundler/vs-esbuild)
- [Single-file executable](https://bun.com/docs/bundler/executables)
- [CSS](https://bun.com/docs/bundler/css)
- [HTML](https://bun.com/docs/bundler/html)
- [Hot Module Replacement (HMR)](https://bun.com/docs/bundler/hmr)
- [Full-stack with HTML imports](https://bun.com/docs/bundler/fullstack)
- Test runner
- [`bun test`](https://bun.com/docs/cli/test)
- [Writing tests](https://bun.com/docs/test/writing)
- [Watch mode](https://bun.com/docs/test/hot)
- [Lifecycle hooks](https://bun.com/docs/test/lifecycle)
- [Mocks](https://bun.com/docs/test/mocks)
- [Snapshots](https://bun.com/docs/test/snapshots)
- [Dates and times](https://bun.com/docs/test/time)
- [DOM testing](https://bun.com/docs/test/dom)
- [Code coverage](https://bun.com/docs/test/coverage)
- [Configuration](https://bun.com/docs/test/configuration)
- [Discovery](https://bun.com/docs/test/discovery)
- [Reporters](https://bun.com/docs/test/reporters)
- [Runtime Behavior](https://bun.com/docs/test/runtime-behavior)
- Package runner
- [`bunx`](https://bun.com/docs/cli/bunx)
- API
- [HTTP server (`Bun.serve`)](https://bun.com/docs/api/http)
- [WebSockets](https://bun.com/docs/api/websockets)
- [Workers](https://bun.com/docs/api/workers)
- [Binary data](https://bun.com/docs/api/binary-data)
- [Streams](https://bun.com/docs/api/streams)
- [File I/O (`Bun.file`)](https://bun.com/docs/api/file-io)
- [import.meta](https://bun.com/docs/api/import-meta)
- [SQLite (`bun:sqlite`)](https://bun.com/docs/api/sqlite)
- [PostgreSQL (`Bun.sql`)](https://bun.com/docs/api/sql)
- [Redis (`Bun.redis`)](https://bun.com/docs/api/redis)
- [S3 Client (`Bun.s3`)](https://bun.com/docs/api/s3)
- [FileSystemRouter](https://bun.com/docs/api/file-system-router)
- [TCP sockets](https://bun.com/docs/api/tcp)
- [UDP sockets](https://bun.com/docs/api/udp)
- [Globals](https://bun.com/docs/api/globals)
- [$ Shell](https://bun.com/docs/runtime/shell)
- [Child processes (spawn)](https://bun.com/docs/api/spawn)
- [Transpiler (`Bun.Transpiler`)](https://bun.com/docs/api/transpiler)
- [Hashing](https://bun.com/docs/api/hashing)
- [Colors (`Bun.color`)](https://bun.com/docs/api/color)
- [Console](https://bun.com/docs/api/console)
- [FFI (`bun:ffi`)](https://bun.com/docs/api/ffi)
- [C Compiler (`bun:ffi` cc)](https://bun.com/docs/api/cc)
- [HTMLRewriter](https://bun.com/docs/api/html-rewriter)
- [Testing (`bun:test`)](https://bun.com/docs/api/test)
- [Cookies (`Bun.Cookie`)](https://bun.com/docs/api/cookie)
- [Utils](https://bun.com/docs/api/utils)
- [Node-API](https://bun.com/docs/api/node-api)
- [Glob (`Bun.Glob`)](https://bun.com/docs/api/glob)
- [Semver (`Bun.semver`)](https://bun.com/docs/api/semver)
- [DNS](https://bun.com/docs/api/dns)
- [fetch API extensions](https://bun.com/docs/api/fetch)
## Guides
- Binary
- [Convert a Blob to a string](https://bun.com/guides/binary/blob-to-string)
- [Convert a Buffer to a blob](https://bun.com/guides/binary/buffer-to-blob)
- [Convert a Blob to a DataView](https://bun.com/guides/binary/blob-to-dataview)
- [Convert a Buffer to a string](https://bun.com/guides/binary/buffer-to-string)
- [Convert a Blob to a ReadableStream](https://bun.com/guides/binary/blob-to-stream)
- [Convert a Blob to a Uint8Array](https://bun.com/guides/binary/blob-to-typedarray)
- [Convert a DataView to a string](https://bun.com/guides/binary/dataview-to-string)
- [Convert a Uint8Array to a Blob](https://bun.com/guides/binary/typedarray-to-blob)
- [Convert a Blob to an ArrayBuffer](https://bun.com/guides/binary/blob-to-arraybuffer)
- [Convert an ArrayBuffer to a Blob](https://bun.com/guides/binary/arraybuffer-to-blob)
- [Convert a Buffer to a Uint8Array](https://bun.com/guides/binary/buffer-to-typedarray)
- [Convert a Uint8Array to a Buffer](https://bun.com/guides/binary/typedarray-to-buffer)
- [Convert a Uint8Array to a string](https://bun.com/guides/binary/typedarray-to-string)
- [Convert a Buffer to an ArrayBuffer](https://bun.com/guides/binary/buffer-to-arraybuffer)
- [Convert an ArrayBuffer to a Buffer](https://bun.com/guides/binary/arraybuffer-to-buffer)
- [Convert an ArrayBuffer to a string](https://bun.com/guides/binary/arraybuffer-to-string)
- [Convert a Uint8Array to a DataView](https://bun.com/guides/binary/typedarray-to-dataview)
- [Convert a Buffer to a ReadableStream](https://bun.com/guides/binary/buffer-to-readablestream)
- [Convert a Uint8Array to an ArrayBuffer](https://bun.com/guides/binary/typedarray-to-arraybuffer)
- [Convert an ArrayBuffer to a Uint8Array](https://bun.com/guides/binary/arraybuffer-to-typedarray)
- [Convert an ArrayBuffer to an array of numbers](https://bun.com/guides/binary/arraybuffer-to-array)
- [Convert a Uint8Array to a ReadableStream](https://bun.com/guides/binary/typedarray-to-readablestream)
- Ecosystem
- [Use React and JSX](https://bun.com/guides/ecosystem/react)
- [Use Gel with Bun](https://bun.com/guides/ecosystem/gel)
- [Use Prisma with Bun](https://bun.com/guides/ecosystem/prisma)
- [Add Sentry to a Bun app](https://bun.com/guides/ecosystem/sentry)
- [Create a Discord bot](https://bun.com/guides/ecosystem/discordjs)
- [Run Bun as a daemon with PM2](https://bun.com/guides/ecosystem/pm2)
- [Use Drizzle ORM with Bun](https://bun.com/guides/ecosystem/drizzle)
- [Build an app with Nuxt and Bun](https://bun.com/guides/ecosystem/nuxt)
- [Build an app with Qwik and Bun](https://bun.com/guides/ecosystem/qwik)
- [Build an app with Astro and Bun](https://bun.com/guides/ecosystem/astro)
- [Build an app with Remix and Bun](https://bun.com/guides/ecosystem/remix)
- [Build a frontend using Vite and Bun](https://bun.com/guides/ecosystem/vite)
- [Build an app with Next.js and Bun](https://bun.com/guides/ecosystem/nextjs)
- [Run Bun as a daemon with systemd](https://bun.com/guides/ecosystem/systemd)
- [Deploy a Bun application on Render](https://bun.com/guides/ecosystem/render)
- [Build an HTTP server using Hono and Bun](https://bun.com/guides/ecosystem/hono)
- [Build an app with SvelteKit and Bun](https://bun.com/guides/ecosystem/sveltekit)
- [Build an app with SolidStart and Bun](https://bun.com/guides/ecosystem/solidstart)
- [Build an HTTP server using Elysia and Bun](https://bun.com/guides/ecosystem/elysia)
- [Build an HTTP server using StricJS and Bun](https://bun.com/guides/ecosystem/stric)
- [Containerize a Bun application with Docker](https://bun.com/guides/ecosystem/docker)
- [Build an HTTP server using Express and Bun](https://bun.com/guides/ecosystem/express)
- [Use Neon Postgres through Drizzle ORM](https://bun.com/guides/ecosystem/neon-drizzle)
- [Server-side render (SSR) a React component](https://bun.com/guides/ecosystem/ssr-react)
- [Read and write data to MongoDB using Mongoose and Bun](https://bun.com/guides/ecosystem/mongoose)
- [Use Neon's Serverless Postgres with Bun](https://bun.com/guides/ecosystem/neon-serverless-postgres)
- HTMLRewriter
- [Extract links from a webpage using HTMLRewriter](https://bun.com/guides/html-rewriter/extract-links)
- [Extract social share images and Open Graph tags](https://bun.com/guides/html-rewriter/extract-social-meta)
- HTTP
- [Hot reload an HTTP server](https://bun.com/guides/http/hot)
- [Common HTTP server usage](https://bun.com/guides/http/server)
- [Write a simple HTTP server](https://bun.com/guides/http/simple)
- [Configure TLS on an HTTP server](https://bun.com/guides/http/tls)
- [Send an HTTP request using fetch](https://bun.com/guides/http/fetch)
- [Proxy HTTP requests using fetch()](https://bun.com/guides/http/proxy)
- [Start a cluster of HTTP servers](https://bun.com/guides/http/cluster)
- [Stream a file as an HTTP Response](https://bun.com/guides/http/stream-file)
- [fetch with unix domain sockets in Bun](https://bun.com/guides/http/fetch-unix)
- [Upload files via HTTP using FormData](https://bun.com/guides/http/file-uploads)
- [Streaming HTTP Server with Async Iterators](https://bun.com/guides/http/stream-iterator)
- [Streaming HTTP Server with Node.js Streams](https://bun.com/guides/http/stream-node-streams-in-bun)
- Install
- [Add a dependency](https://bun.com/guides/install/add)
- [Add a Git dependency](https://bun.com/guides/install/add-git)
- [Add a peer dependency](https://bun.com/guides/install/add-peer)
- [Add a trusted dependency](https://bun.com/guides/install/trusted)
- [Add a development dependency](https://bun.com/guides/install/add-dev)
- [Add a tarball dependency](https://bun.com/guides/install/add-tarball)
- [Add an optional dependency](https://bun.com/guides/install/add-optional)
- [Generate a yarn-compatible lockfile](https://bun.com/guides/install/yarnlock)
- [Configuring a monorepo using workspaces](https://bun.com/guides/install/workspaces)
- [Install a package under a different name](https://bun.com/guides/install/npm-alias)
- [Install dependencies with Bun in GitHub Actions](https://bun.com/guides/install/cicd)
- [Using bun install with Artifactory](https://bun.com/guides/install/jfrog-artifactory)
- [Configure git to diff Bun's lockb lockfile](https://bun.com/guides/install/git-diff-bun-lockfile)
- [Override the default npm registry for bun install](https://bun.com/guides/install/custom-registry)
- [Using bun install with an Azure Artifacts npm registry](https://bun.com/guides/install/azure-artifacts)
- [Migrate from npm install to bun install](https://bun.com/guides/install/from-npm-install-to-bun-install)
- [Configure a private registry for an organization scope with bun install](https://bun.com/guides/install/registry-scope)
- Process
- [Read from stdin](https://bun.com/guides/process/stdin)
- [Listen for CTRL+C](https://bun.com/guides/process/ctrl-c)
- [Spawn a child process](https://bun.com/guides/process/spawn)
- [Listen to OS signals](https://bun.com/guides/process/os-signals)
- [Parse command-line arguments](https://bun.com/guides/process/argv)
- [Read stderr from a child process](https://bun.com/guides/process/spawn-stderr)
- [Read stdout from a child process](https://bun.com/guides/process/spawn-stdout)
- [Get the process uptime in nanoseconds](https://bun.com/guides/process/nanoseconds)
- [Spawn a child process and communicate using IPC](https://bun.com/guides/process/ipc)
- Read file
- [Read a JSON file](https://bun.com/guides/read-file/json)
- [Check if a file exists](https://bun.com/guides/read-file/exists)
- [Read a file as a string](https://bun.com/guides/read-file/string)
- [Read a file to a Buffer](https://bun.com/guides/read-file/buffer)
- [Get the MIME type of a file](https://bun.com/guides/read-file/mime)
- [Watch a directory for changes](https://bun.com/guides/read-file/watch)
- [Read a file as a ReadableStream](https://bun.com/guides/read-file/stream)
- [Read a file to a Uint8Array](https://bun.com/guides/read-file/uint8array)
- [Read a file to an ArrayBuffer](https://bun.com/guides/read-file/arraybuffer)
- Runtime
- [Delete files](https://bun.com/guides/runtime/delete-file)
- [Run a Shell Command](https://bun.com/guides/runtime/shell)
- [Import a JSON file](https://bun.com/guides/runtime/import-json)
- [Import a TOML file](https://bun.com/guides/runtime/import-toml)
- [Set a time zone in Bun](https://bun.com/guides/runtime/timezone)
- [Set environment variables](https://bun.com/guides/runtime/set-env)
- [Re-map import paths](https://bun.com/guides/runtime/tsconfig-paths)
- [Delete directories](https://bun.com/guides/runtime/delete-directory)
- [Read environment variables](https://bun.com/guides/runtime/read-env)
- [Import a HTML file as text](https://bun.com/guides/runtime/import-html)
- [Install and run Bun in GitHub Actions](https://bun.com/guides/runtime/cicd)
- [Debugging Bun with the web debugger](https://bun.com/guides/runtime/web-debugger)
- [Install TypeScript declarations for Bun](https://bun.com/guides/runtime/typescript)
- [Debugging Bun with the VS Code extension](https://bun.com/guides/runtime/vscode-debugger)
- [Inspect memory usage using V8 heap snapshots](https://bun.com/guides/runtime/heap-snapshot)
- [Define and replace static globals & constants](https://bun.com/guides/runtime/define-constant)
- [Codesign a single-file JavaScript executable on macOS](https://bun.com/guides/runtime/codesign-macos-executable)
- Streams
- [Convert a ReadableStream to JSON](https://bun.com/guides/streams/to-json)
- [Convert a ReadableStream to a Blob](https://bun.com/guides/streams/to-blob)
- [Convert a ReadableStream to a Buffer](https://bun.com/guides/streams/to-buffer)
- [Convert a ReadableStream to a string](https://bun.com/guides/streams/to-string)
- [Convert a ReadableStream to a Uint8Array](https://bun.com/guides/streams/to-typedarray)
- [Convert a ReadableStream to an array of chunks](https://bun.com/guides/streams/to-array)
- [Convert a Node.js Readable to JSON](https://bun.com/guides/streams/node-readable-to-json)
- [Convert a ReadableStream to an ArrayBuffer](https://bun.com/guides/streams/to-arraybuffer)
- [Convert a Node.js Readable to a Blob](https://bun.com/guides/streams/node-readable-to-blob)
- [Convert a Node.js Readable to a string](https://bun.com/guides/streams/node-readable-to-string)
- [Convert a Node.js Readable to an Uint8Array](https://bun.com/guides/streams/node-readable-to-uint8array)
- [Convert a Node.js Readable to an ArrayBuffer](https://bun.com/guides/streams/node-readable-to-arraybuffer)
- Test
- [Spy on methods in `bun test`](https://bun.com/guides/test/spy-on)
- [Bail early with the Bun test runner](https://bun.com/guides/test/bail)
- [Mock functions in `bun test`](https://bun.com/guides/test/mock-functions)
- [Run tests in watch mode with Bun](https://bun.com/guides/test/watch-mode)
- [Use snapshot testing in `bun test`](https://bun.com/guides/test/snapshot)
- [Skip tests with the Bun test runner](https://bun.com/guides/test/skip-tests)
- [Using Testing Library with Bun](https://bun.com/guides/test/testing-library)
- [Update snapshots in `bun test`](https://bun.com/guides/test/update-snapshots)
- [Run your tests with the Bun test runner](https://bun.com/guides/test/run-tests)
- [Set the system time in Bun's test runner](https://bun.com/guides/test/mock-clock)
- [Set a per-test timeout with the Bun test runner](https://bun.com/guides/test/timeout)
- [Migrate from Jest to Bun's test runner](https://bun.com/guides/test/migrate-from-jest)
- [Write browser DOM tests with Bun and happy-dom](https://bun.com/guides/test/happy-dom)
- [Mark a test as a "todo" with the Bun test runner](https://bun.com/guides/test/todo-tests)
- [Re-run tests multiple times with the Bun test runner](https://bun.com/guides/test/rerun-each)
- [Generate code coverage reports with the Bun test runner](https://bun.com/guides/test/coverage)
- [import, require, and test Svelte components with bun test](https://bun.com/guides/test/svelte-test)
- [Set a code coverage threshold with the Bun test runner](https://bun.com/guides/test/coverage-threshold)
- Util
- [Generate a UUID](https://bun.com/guides/util/javascript-uuid)
- [Hash a password](https://bun.com/guides/util/hash-a-password)
- [Escape an HTML string](https://bun.com/guides/util/escape-html)
- [Get the current Bun version](https://bun.com/guides/util/version)
- [Encode and decode base64 strings](https://bun.com/guides/util/base64)
- [Compress and decompress data with gzip](https://bun.com/guides/util/gzip)
- [Sleep for a fixed number of milliseconds](https://bun.com/guides/util/sleep)
- [Detect when code is executed with Bun](https://bun.com/guides/util/detect-bun)
- [Check if two objects are deeply equal](https://bun.com/guides/util/deep-equals)
- [Compress and decompress data with DEFLATE](https://bun.com/guides/util/deflate)
- [Get the absolute path to the current entrypoint](https://bun.com/guides/util/main)
- [Get the directory of the current file](https://bun.com/guides/util/import-meta-dir)
- [Check if the current file is the entrypoint](https://bun.com/guides/util/entrypoint)
- [Get the file name of the current file](https://bun.com/guides/util/import-meta-file)
- [Convert a file URL to an absolute path](https://bun.com/guides/util/file-url-to-path)
- [Convert an absolute path to a file URL](https://bun.com/guides/util/path-to-file-url)
- [Get the absolute path of the current file](https://bun.com/guides/util/import-meta-path)
- [Get the path to an executable bin file](https://bun.com/guides/util/which-path-to-executable-bin)
- WebSocket
- [Build a publish-subscribe WebSocket server](https://bun.com/guides/websocket/pubsub)
- [Build a simple WebSocket server](https://bun.com/guides/websocket/simple)
- [Enable compression for WebSocket messages](https://bun.com/guides/websocket/compression)
- [Set per-socket contextual data on a WebSocket](https://bun.com/guides/websocket/context)
- Write file
- [Delete a file](https://bun.com/guides/write-file/unlink)
- [Write to stdout](https://bun.com/guides/write-file/stdout)
- [Write a file to stdout](https://bun.com/guides/write-file/cat)
- [Write a Blob to a file](https://bun.com/guides/write-file/blob)
- [Write a string to a file](https://bun.com/guides/write-file/basic)
- [Append content to a file](https://bun.com/guides/write-file/append)
- [Write a file incrementally](https://bun.com/guides/write-file/filesink)
- [Write a Response to a file](https://bun.com/guides/write-file/response)
- [Copy a file to another location](https://bun.com/guides/write-file/file-cp)
- [Write a ReadableStream to a file](https://bun.com/guides/write-file/stream)
## Contributing
Refer to the [Project > Contributing](https://bun.com/docs/project/contributing) guide to start contributing to Bun.
## License
Refer to the [Project > License](https://bun.com/docs/project/licensing) page for information about Bun's licensing.