Modern applications run on APIs — and knowing how to design and build them well is one of the most valuable skills a backend developer can have. Whether you're powering a mobile app, connecting a frontend to a database, or exposing services for third-party integrations, a well-structured REST API is almost always at the center of it all. This course takes you from the ground up, starting with the core concepts of REST and HTTP, then moving into hands-on work with Node.js and Express. You'll learn how to structure routes and controllers cleanly, handle request data through params, query strings, and request bodies, and build out full CRUD functionality against a real data source. Along the way, you'll tackle the practical challenges every API developer faces: input validation, meaningful error responses, and protecting endpoints with authentication middleware. By the time you finish, you'll be able to design and ship a production-ready REST API — one that's organized, handles errors gracefully, and follows conventions that other developers can immediately understand and work with. This course is a great fit for developers who already know JavaScript fundamentals and want to move into backend work, or for those who've tinkered with Node.js but want a structured, end-to-end understanding of how real APIs are built. No prior backend or API experience is required. If you're ready to go from "I've heard of Express" to building and deploying your own REST API with confidence, this is where you start.