Bun Runtime

Move fast with the Bun runtime for JavaScript and TypeScript. Covers the package manager, bundler, test runner, and native APIs, plus migrating an existing Node.js project to Bun for lower cold starts and faster installs.

This skill helps you build and ship with Bun — the all-in-one JavaScript/TypeScript runtime. It uses Bun's fast package manager and bundler, writes tests with the built-in test runner, taps native APIs like Bun.serve and the SQLite driver, and migrates Node.js projects across incrementally, flagging the Node APIs that need adjustment along the way.

When to use

Use when developing with Bun, managing packages or bundling with Bun, writing tests with bun:test, using native Bun APIs, or migrating a Node.js project to Bun for speed.

Examples

Migrate Node to Bun

Move a project onto Bun

Migrate this Express + Node.js service to run on Bun, replacing Node-specific APIs with Bun equivalents and switching the test runner to bun:test

Bun HTTP server

Serve requests with Bun.serve

Build a small JSON API with Bun.serve including routing, request validation, and the built-in SQLite driver for persistence

Fast test setup

Wire up bun:test

Set up a bun:test suite with mocks and coverage for this TypeScript module and add a watch script