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 box The bun command-line tool also implements a test runner, script runner, and Node.js-compatible package manager, all significantly faster than existing tools and usable in existing Node.js projects with little to no changes necessary.

bun run start # run the start script bun install # install a package bun build ./index.tsx # bundle a project for browsers bun test # run tests bunx cowsay 'Hello, world!' # execute a package Get started with one of the quick links below, or read on to learn more about Bun.