What is Bun?

Bun is a JavaScript runtime written in Zig, developed as a fast alternative to Node.js. It uses the JavaScriptCore engine and is largely compatible with Node.js modules.

It can run npm packages, supports TypeScript directly, and comes with a built-in test runner.

Core Features

Bun combines four core functions into a single tool: package manager, test runner, bundler, and runtime. It installs packages up to 10x faster than npm.

With built-in TypeScript support, no additional configuration is required.

Node.js Compatibility

Bun supports most Node.js APIs. Built-in modules like fs, path, and http work on Bun. However, full compatibility for some native modules may be expected.

Node.js API compatibility npm package support TypeScript and JSX support Built-in Web APIs (fetch, WebSocket)

Performance Comparison

Bun is noticeably faster than Node.js, especially in package installation, script execution, and HTTP requests. SQLite binding also comes built-in.

Use Cases

Bun is ideal for rapid prototyping, API development, script execution, and testing processes. However, some Node.js projects may experience compatibility issues.