Build Bulletproof APIs using TypeScript in Express

<p>If you've ever loved the speed of building backend servers with Express.js, but wished you didn't have to guess at types or debug silly runtime errors, we just posted the perfect tutorial for you.</p> <p>Our new video course, TypeScript in Express, is now live on the freeCodeCamp.org YouTube channel!</p> <p>In this hands-on tutorial, instructor Rachel takes you step-by-step through combining Express with TypeScript, giving you the best of both worlds: the rapid development speed of Express paired with the scalability, reliability, and robust safety of strong typing.</p> <p>Throughout the course, you’ll build a fully typed, production-ready pet shelter API from scratch. Along the way, you'll tackle:</p> <ul> <li><p>Environment Setup: Configuring TypeScript, setting up compiler options (<code>tsconfig.json</code>), and managing development dependencies like <code>@types/express</code>.</p> </li> <li><p>Request &amp; Response Typing: Moving away from the dreaded <code>any</code> type by leveraging TypeScript generics to strictly define route parameters, request queries, and response bodies.</p> </li> <li><p>Modular Architecture: Cleaning up your project structure by separating your endpoints into dedicated Express routers and controllers.</p> </li> <li><p>Custom Middleware: Writing and typing your own middleware functions from scratch—including input validators and authentication checks.</p> </li> <li><p>Query Parameter Filtering: Handling string, boolean, and numeric query filters to make your APIs flexible and real-world ready.</p> </li> </ul> <p>Whether you're looking to solidify your backend skills or bring stronger type safety to your Node.js projects, this course is packed with practical challenges and coding exercises to keep you on your toes.</p> <p>Watch the full tutorial <a href="https://youtu.be/bYgphDEWwvs">on the freeCodeCamp.org YouTube channel</a> (1-hour watch).</p> <div class="embed-wrapper"><iframe width="560" height="315" src="https://www.youtube.com/embed/bYgphDEWwvs" style="aspect-ratio: 16 / 9; width: 100%; height: auto;" title="YouTube video player" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen="" loading="lazy"></iframe></div>