Bun

Specification

The words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL are interpreted as described in RFC 2119.

Use Bun deliberately. Prefer Bun-native APIs in Bun-first projects, but do not break portability by accident.

Bun is an all-in-one JavaScript and TypeScript toolkit: runtime, package manager, test runner, bundler, and script runner. In projects that intentionally target Bun, you SHOULD prefer Bun-native APIs such as Bun.serve, Bun.file, Bun.write, Bun.$, Bun.spawn, bun:sqlite, and bun:test. In existing Node-compatible projects, you MUST respect the established portability contract and only introduce Bun-specific APIs when the project is already Bun-targeted or the user asks for Bun-specific implementation.