The JavaScript Runtime War

The battle between JavaScript runtimes has intensified in 2025. Bun has matured significantly since its 1.0 release, while Node.js continues to evolve with v22 LTS. Let’s break down which one you should pick for your next project.

Performance Benchmarks

In our tests across common workloads:

  • HTTP Server: Bun serves ~2.5x more requests/second than Node.js
  • File I/O: Bun reads files ~3x faster using native APIs
  • Package Install: bun install is 5-10x faster than npm install
  • Startup Time: Bun starts in ~6ms vs Node’s ~30ms
  • TypeScript: Bun runs .ts files natively — no build step needed

When to Choose Bun

  • New projects without legacy dependencies
  • API servers where raw performance matters
  • Scripts and CLI tools that need fast startup
  • Monorepos where install speed saves CI minutes
  • TypeScript-first projects (no tsconfig needed)

When to Stick with Node.js

  • Enterprise projects with strict stability requirements
  • AWS Lambda (Bun runtime support is still limited)
  • Projects with native addons (node-gyp compatibility varies)
  • Teams already invested in Node.js tooling
  • Production apps that need LTS support guarantees

Migration Tips

If you’re considering switching from Node to Bun:

  1. Test your dependencies with bun install — most npm packages work
  2. Replace jest with Bun’s built-in test runner
  3. Remove your tsconfig.json build step (Bun handles it)
  4. Update your Dockerfile: FROM oven/bun:1
  5. Run your test suite — fix any incompatibilities

Verdict

For new projects in 2025, Bun is the better default choice unless you have specific Node.js requirements. The performance gains are real, the DX is superior, and the compatibility gap has largely closed.