Fundamentals of Express.js and Node

Express remains one of the cleanest ways to learn backend fundamentals. Every conceptrouting, middleware, error handlingis small and explicit.

Requests, responses, and middleware

I structure apps around three things: route handlers that stay small, middleware for cross-cutting concerns (auth, logging, parsing), and dedicated modules for business logic. This keeps controllers thin and makes it much easier to test logic without spinning up an entire HTTP server.

Error handling as a first-class feature

A single error-handling middleware at the bottom of the stack is where I normalize all errors into a consistent JSON shape. That handler logs internal details while returning safe user-facing messages. Once this exists, new routes simply throw errors when something goes wrong.