Hello readers 👋, welcome to the 9th blog in our Node.js series! In our last post, we learned how JWT authentication keeps your application secure without the need for server-side sessions. Today, we're going to focus on something equally essential: how to design a clean, predictable, and intuitive API using Express.js following REST principles. Whether you're building a mobile app, a frontend in React, or just exposing data to the world, you'll need an API that clients can understand and use easily. REST gives us a set of conventions that make APIs feel natural. We'll break down what a REST API is, map out HTTP methods, introduce status codes, and design routes for a simple users resource. By the end, you'll be able to structure your own Express.js APIs clearly. Let's jump right in. What is a REST API? First, let's define API . An API (Application Programming Interface) is a set of rules that allows two pieces of software to talk to each other.…