I've been using Node.js for years but keep hearing about Bun being way faster. I'm running a Express server handling about 1000 requests per minute and wondering if switching would actually make a difference or if it's just hype. Has anyone actually migrated a production app over?
The migration itself is where you'll actually feel pain. Express runs on Node.js, so you'd need to rewrite your server logic for Bun's API (or use a compatibility layer that defeats the purpose), test everything from scratch, and deal with potential library incompatibilities. At 1000 requests per minute, you're right that the runtime speed probably isn't your actual problem - if it were, you'd see your CPU maxed out, not your database queries taking forever. Unless you're hitting genuine performance walls and have time to experiment, staying put is the practical call.
Bun is genuinely faster than Node.js in raw benchmarks, but at 1000 requests per minute your bottleneck is probably your database or application logic, not the runtime itself. The real question is whether your Express code even runs on Bun without rewrites (some packages still don't play nice), so unless you're hitting performance walls that profiling clearly points to the runtime, the migration hassle probably isn't worth it.
The real bottleneck test is profiling your actual app - run it under load and see where the time goes before you commit to a migration. Yeah, Bun handles raw throughput better in benchmarks, but at your scale you're probably waiting on database queries or external API calls, not JavaScript execution. One thing people gloss over: migrating from Express means checking compatibility because Bun's Node.js emulation layer doesn't cover everything perfectly yet, and some popular packages might behave differently or need tweaks. If your app is already running smoothly at 1000 requests per minute, the gains from switching probably won't be worth the migration headache unless you're planning to scale way higher.
At 1000 requests per minute you're probably not hitting runtime limitations yet - that's pretty modest traffic. Before you even think about switching, try running your current setup through a profiler like clinic.js or Node's built-in inspector to see what's actually slow (usually it's database queries or external API calls, not JavaScript execution). If you do decide to experiment, spin up a small Bun instance alongside your Node server and load test both with your real traffic patterns rather than synthetic benchmarks. One thing people skip: check if your Express dependencies have Bun alternatives or native support - some popular middleware won't work out of the box, and that hidden compatibility layer becomes your real performance tax.
Log into answer.
