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BunRuntimePerformance

Why I Chose Bun Over Node.js

Why I Chose Bun Over Node.js
6 min read

After months of using Bun in production, here's my honest take on performance, DX, and the trade-offs you should know.

I switched my entire development workflow to Bun six months ago. Here's what I've learned.

The Promise

Bun claims to be:

  • 10x faster than Node.js
  • Drop-in compatible with Node.js packages
  • All-in-one runtime, bundler, test runner, package manager

Sounds too good to be true? Let's see.

Performance Is Real

The performance claims aren't marketing fluff:

# Cold start comparison
Node.js: ~500ms
Bun: ~50ms

For development servers, this matters. No more waiting 3 seconds for npm run dev to start.

The DX Upgrade

Install & Run (One Tool)

# Before (Node.js)
npm install
node index.js
 
# After (Bun)
bun install
bun index.js

Same commands, faster execution. bun install is notably faster than npm install.

Built-in Bundler

# Before
npm install -D webpack esbuild
npm run build
 
# After
bun build ./src/index.ts --outdir ./dist

No config needed. Just works.

Native Test Runner

// test/math.test.ts
import { test, expect } from "bun:test";
 
test("addition", () => {
  expect(1 + 1).toBe(2);
});

Run with bun test. No Jest, no config.

The Trade-offs

Bun isn't perfect. Here's where it struggles:

1. Ecosystem Maturity

  • Some native addons don't work
  • Debugging tools aren't as mature
  • Smaller community = fewer Stack Overflow answers

2. Edge Cases

I've hit a few bugs:

  • Bun.glob() not available in some versions
  • Certain Node.js APIs not fully implemented
  • Occasional TypeScript weirdness

3. Production Monitoring

If your company uses APM tools built for Node.js, they might not work with Bun yet.

What Works Great

  • API servers: Fast startup, low latency
  • Scripts: Single-command execution
  • Frontend builds: Vite + Next.js work perfectly
  • File operations: Bun.file() and Bun.write() are excellent

My Recommendation

Use Bun if:

  • You're starting a new project
  • Performance matters
  • You want simpler tooling

Stick with Node.js if:

  • You rely on specific native modules
  • Your team uses Node.js-specific tooling
  • You need enterprise-grade monitoring

Real-World Results

For my portfolio site:

  • Build time: 45s → 12s
  • Dev server start: 3.2s → 0.4s
  • Bundle size: Unchanged

The speed improvements are real.

Final Thoughts

Bun isn't replacing Node.js tomorrow. But for greenfield projects and personal work, it's my default choice.

The developer experience alone is worth it — faster iteration, fewer tools, less config.

Give it a try on your next side project. You might not go back.

Switched to Bun in 2024 · Never looked back