Why I Switched from Node.js to Bun (And My Honest Take After 6 Months)

Six months ago I nuked Node.js from BetterStarter's toolchain and replaced it with Bun. No gradual migration — just ripped out the old, dropped in the new, and shipped.

Here's the honest story of why I did it, what actually happened, and whether you should do it too.

The Node.js Pain That Finally Broke Me

I want to be clear: I don't hate Node.js. It's served me well for years. But by the time I was building BetterStarter, I'd accumulated a specific set of frustrations that had become genuinely productivity-killing.

`npm install` Is an Exercise in Patience

I know you've felt this. You clone a repo, run npm install, and then go make a coffee. Sometimes you make lunch. The node_modules directory becomes a black hole that eats disk space and CI minutes in equal measure.

For BetterStarter — which has auth, Stripe, email, Drizzle, TanStack Start, and a full shadcn/ui setup — a fresh npm install was regularly hitting 45–60 seconds in CI. That's 45 seconds every single time a PR opens. It adds up fast.

TypeScript With `ts-node` Was a Jank Nightmare

You've got your Node.js project, you want to run a TypeScript file — a seed script, a migration runner, a one-off utility. And then you need ts-node, or tsx, or ts-node-esm, and half the time there's some ESM/CJS conflict error that costs you 20 minutes to debug.

I spent an embarrassing amount of time in 2023 reading Stack Overflow threads about "type": "module" vs "type": "commonjs" and what that means for __dirname. That's not time spent building. That's time spent fighting tooling.

Jest Configuration Hell

The final straw was Jest. Setting up Jest for a TypeScript + ESM project requires a Babel config, or a ts-jest transformer, or some incantation in jest.config.js that nobody fully understands but everyone copies from Stack Overflow. Then you upgrade a dependency, something breaks, and you're back to spelunking.

I added the 47th line to a jest.config.js file and thought: there has to be a better way.

Why I Tried Bun

The pitch for Bun is simple:

Runs TypeScript natively, no transpilation step
Blazing fast package installs
Built-in test runner
Drop-in Node.js compatibility

I'd watched the Bun 1.0 release in September 2023 and been skeptical — "another runtime that'll never reach production maturity." But by mid-2025, with Bun pushing toward 1.x stability, the ecosystem support had grown enough that I decided to actually try it on something real.

BetterStarter was the guinea pig.

The Migration: What Actually Happened

The Good Stuff First

Install speed is not a joke. Running bun install on BetterStarter's full dependency tree takes 8–12 seconds compared to 45–60 seconds with npm. That's a 4–5x improvement that makes a real difference in CI and especially in local git clone → start developing loops.

In absolute numbers, for our CI pipeline that runs on every PR, that's 35+ seconds saved per run. If you're opening 5 PRs a day across a team, you've just saved 3+ minutes of waiting per developer per day. It's not earth-shattering, but it's real and cumulative.

TypeScript just works. bun run seed.ts. That's it. No ts-node. No Babel. No config. Bun reads TypeScript natively and executes it. This alone removed about 4 packages from our devDependencies and an entire babel.config.js file.

The test runner is fast and the API is familiar. Bun's built-in test runner uses a Jest-compatible API — describe, it, expect, beforeEach — so migrating tests is basically a find-and-replace of jest imports. Our test suite that took 14 seconds with Jest runs in 3.2 seconds with Bun.

I want to sit with that for a second: 14 seconds → 3.2 seconds. When you're doing TDD or running tests on every save, that feedback loop compression is enormous.

Startup time. Bun starts significantly faster than Node.js. For a long-running server this matters less, but for scripts, CLIs, or serverless-style invocations, you feel the difference immediately.

Here's a quick comparison from my own measurements on the BetterStarter codebase:

# Package install (full node_modules, cold cache)
npm install    → 52s
bun install    → 10s

# Run a TypeScript script
ts-node seed.ts     → 3.1s (including ts-node startup)
bun run seed.ts     → 0.4s

# Test suite (47 tests)
jest            → 14.2s
bun test        → 3.2s

These are real numbers from my machine (M2 MacBook Pro). Your mileage will vary, but the ratios are consistent.

What Broke During Migration

Let's be honest about the rough edges — because there are some.

Some Packages Have Edge Cases

Most packages work fine. The compatibility layer is genuinely impressive. But I hit a couple of packages that had subtle issues:

One of BetterStarter's email dependencies had an issue with Bun's node:crypto compatibility that took me about an hour to track down. The fix was a one-liner, but the debugging process wasn't obvious. The Bun GitHub issues tracker is your friend here — most edge cases have already been reported and often have workarounds documented.

Rule of thumb: If you're using a package that does low-level native Node.js stuff (native addons, specific buffer operations, certain stream internals), test it explicitly before committing to Bun.

Windows Support Is Still a Work In Progress

This is a real limitation you need to know about. Windows support in Bun has improved but it's not at parity with macOS/Linux. If your team has Windows developers, you'll either need WSL2 (which generally works fine) or you'll hit occasional friction.

For BetterStarter, our primary audience is macOS/Linux developers, so this hasn't been a blocker. But if you're building a tool or a boilerplate targeting Windows-heavy teams, factor this in.

The Bun Lockfile

Bun uses bun.lockb — a binary lockfile — instead of package-lock.json or yarn.lock. This means:

Git diffs on lockfile changes are unreadable (the file is binary)
Collaborators need Bun installed to reproduce installs

Neither is a dealbreaker, but it's a coordination cost if you're working with a team that isn't fully on Bun yet.

`Bun.serve()` vs Your Framework

If you're using Bun's native HTTP server (Bun.serve()), you get amazing performance. But most people (including us with TanStack Start) are using a framework that ultimately abstracts over the server layer. The framework compatibility story is solid for most major frameworks, but it's worth verifying your specific stack works end-to-end before migrating.

Real Benchmarks: HTTP Performance

I've seen the benchmarks that claim Bun is 2x–3x faster than Node.js for HTTP throughput. In my honest experience:

For a typical SaaS app with database queries, the bottleneck is almost never the runtime. It's the DB round trips, the external API calls, the rendering work. So in practice, I haven't seen massive real-world HTTP performance differences for BetterStarter's use case.

Where Bun genuinely shines in production is startup time and resource efficiency — BetterStarter's server process uses noticeably less memory under the same load. For serverless or containerized deployments where you're paying for memory, that matters.

Current Verdict: Should You Switch from Node.js to Bun?

After six months in production: yes, for new projects. Careful for existing ones.

For new projects: Start with Bun. The DX improvements are real and meaningful. You'll have a faster install loop, faster tests, native TypeScript execution, and a slightly more modern feel. The ecosystem compatibility is good enough that you're unlikely to hit blockers for typical SaaS/web development work.

For existing projects: Evaluate your risk tolerance. If you have a large, stable codebase with many dependencies, do a thorough audit of your package compatibility before migrating. The wins are real, but the migration isn't zero-effort.

For teams with Windows developers: Test on Windows first. Either commit to WSL2 or wait for Windows support to mature further.

This same philosophy of "make the right call on tooling early" is what drove how I set up BetterStarter. Just like why I switched from Next.js to TanStack Start, the decision to adopt Bun was about eliminating entire categories of friction before they compound.

What BetterStarter's Stack Looks Like With Bun

BetterStarter ships on Bun. When you clone the repo and run bun install, you're up and running in under 15 seconds. The dev server starts in under a second. Tests run in a few seconds.

That's the experience I wanted: you buy the boilerplate, you clone it, and you're writing actual product code within minutes — not fighting TypeScript configs or wondering why Jest won't find your test files.

The TanStack Start boilerplate architecture I built is designed around this kind of lean, fast toolchain. Bun is a core part of that.

If you're building a SaaS and want to start on Bun without manually setting up auth, Stripe, email, and database migrations, BetterStarter ships all of that pre-configured for a one-time $99. You skip the boilerplate work and start shipping features.

The Six-Month Summary

Here's the honest scorecard after six months running BetterStarter on Bun in production:

Area	Before (Node.js)	After (Bun)
`bun install` speed	~52s	~10s
TypeScript execution	ts-node + config	Native, zero config
Test speed (47 tests)	14.2s (Jest)	3.2s (bun test)
Config files removed	—	babel.config.js, ts-node setup
Production issues	0	0
Windows support	✅	⚠️ (WSL2 recommended)

The wins are real. The rough edges are manageable. The decision to switch was correct.

FAQ: Switching from Node.js to Bun

Is Bun ready for production in 2025? Yes, for most web and SaaS workloads. Bun 1.x has strong Node.js compatibility, and many teams are running it in production successfully. The main caveats are Windows support and occasional package edge cases with native Node.js APIs.

How hard is it to migrate an existing Node.js project to Bun? For most projects, it's surprisingly straightforward. Replace node with bun, npm with bun, and npx with bunx. The main work is auditing your dependencies for compatibility and replacing ts-node or jest with Bun's native equivalents.

Is Bun actually faster than Node.js? Yes, especially for startup time, package installs, and test execution. For raw HTTP throughput on a typical database-backed SaaS app, the runtime speed difference is less impactful than you might expect — the bottleneck is usually I/O, not the runtime.

Does Bun work with TanStack Start? Yes. BetterStarter runs TanStack Start on Bun in production. There are no compatibility issues with the TanStack router or server functions.

What's the biggest risk of switching to Bun? Packages that rely on native Node.js addons or very specific internal Node.js APIs may have edge cases. Test your critical dependencies explicitly before migrating, especially anything touching node:crypto, native modules, or obscure stream internals.