FREE CODING COURSES

Free Programming Course: Zero to Interview-Ready

Pick a language to start. Every lesson is interactive: write the code in your browser and check each step as you go. Try the first step of any lesson free, no sign-up needed.

Py PythonReadable and forgiving. The most popular choice for coding interviews. JS JavaScriptThe language of the web, from first variables to interview problems. Jv JavaStrong types and classes, the classic big-company interview language. C++ C++Fast and precise. Great for algorithms and competitive programming. C# C#Modern, typed and versatile, from games to backend services. TS TypeScriptJavaScript with types that catch mistakes before you run. Kt KotlinConcise and safe, the modern language for Android and the JVM. Sc ScalaFunctional and object-oriented ideas in one expressive language. Go GoSimple, fast and built for servers and tools. Sw SwiftClean, safe code for Apple platforms and beyond. Rs RustMemory-safe speed, with a compiler that teaches as it checks.

SD PART 4 OF EVERY COURSESystem designDesign real systems one decision at a time: the building blocks, then Twitter, Uber, payments and more, the way interviews ask. 140 lessons