Express.js: APIs That Stay Maintainable

Express.js is a minimal web framework for Node.js. It handles HTTP requests and responses, routing, and middleware, giving you a simple way to build REST APIs. The core idea is middleware: small functions that run in sequence for each request. You can use them to log requests, check authentication, parse JSON bodies, or handle errors. Use Express.js when you need full control over your API structure without a heavy framework. It is great for learning backend fundamentals and still powers many production systems. Simple conceptual example: - app.get('/api/users') to return a list of users - app.post('/api/users') to create a new user - app.use(errorHandler) to handle errors in one place Express becomes even more powerful with TypeScript and proper folder structure: routes, controllers, services, and database layers separated clearly.