Bun

Bun is a JavaScript runtime, bundler, transpiler, package manager, and test runner built in Zig around the JavaScriptCore engine (the same engine that powers Safari). Bun positions itself as a drop-in replacement for Node.js with substantially faster startup, install, and execution times.

What ships in one binary

• Runtime. Executes JavaScript and TypeScript with native TS, JSX, and import support.
• Package manager. bun install is several times faster than npm or pnpm.
• Bundler. bun build bundles for browser and server targets.
• Test runner. Jest-compatible matchers, native TS, parallel execution.
• Node.js API compatibility. Targets parity with Node for most modules.

Notable features

• Native SQLite, S3, HTTP, WebSocket, file system APIs
• Single-binary distribution; no separate compiler or runner
• Hot reloading in development with bun --hot
• Edge deployment platforms support Bun (Cloudflare Workers, Vercel)