Express.js

Express defined how Node.js backend applications were built. Middleware chains, routing, and a minimal core that lets you compose your own stack. It works and it's everywhere.

The problem is what it lacks. No built-in TypeScript support, no type-safe routing, no validation layer, no WebSocket integration. Every Express project reinvents the same boilerplate. Elysia on Bun gives you all of this out of the box with better performance and end-to-end type safety. Existing Express apps run fine — new projects should start elsewhere.