Bun

Bun is a drop-in replacement for Node.js, written in Zig. It is fast. v1.1 brings Windows support.

When to Use

• Speed: bun install is instant. bun run starts instantly.
• Local Dev: Use it as a package manager even if you use Node.js for production.
• Testing: bun test is a fast, Jest-compatible test runner.

Core Concepts

Drop-in Replacement

Implements Node APIs (fs, http, path).

Bundle / Transpile

Built-in transpiler for TS/JSX.

Macros

Run code at build time.

Best Practices (2025)

Do:

• Use bun install: It's compatible with package-lock.json but faster.
• Use bun test: It's much faster than Jest/Vitest.
• Use Bun.serve: For max performance HTTP servers.

Don't:

• Don't use for everything: Some niche Node C++ addons might still have issues.

References

• Bun Documentation