Middleware is one of those terms that can feel intimidating when you first encounter Express.js. But once you understand it, you’ll realize it’s the secret sauce that makes Express flexible, modular, and powerful. Let’s break it down in plain language and walk through a practical example. 🚦 What Exactly Is Middleware? Middleware functions are like checkpoints in your app. Every request that comes in passes through them before reaching its destination. They can inspect the request (headers, body, params). They can transform the request or response. They can end the cycle (send a response). Or they can pass control to the next middleware using next() . Think of middleware as a series of filters — each one has a job, and together they shape how your app behaves. 🛠️ Anatomy of Middleware Here’s the simplest middleware function: function middleware(req, res, next) { console.log('Request received at:', new Date()); next(); // move to the next middleware } req ...