Express.js API Patterns

Build Express.js APIs the right way. Structures routes and middleware, centralizes error handling, validates requests, and configures CORS so your Node backend stays maintainable as it grows.

This skill helps you build clean Express.js backends. It organizes routers and controllers, layers middleware in the correct order, adds a centralized error-handling middleware, validates request bodies and params, configures CORS and security headers, and sets up async route wrappers so rejected promises do not crash the server.

When to use

Use when building Express routes, implementing middleware, handling API requests and errors, validating input, or setting up a Node backend server.

Examples

Structured route + middleware

Lay out a maintainable API

Set up an Express API with a router, controller, validation middleware, centralized error handler, and an async wrapper to catch rejected promises

Request validation + CORS

Harden an endpoint

Add request body validation and a CORS policy that only allows my frontend origin to this Express route