System Architecture of React Playground: What Actually Happens Behind the Scenes

In the previous blog , I talked about what I built and the problems I faced. This time, I want to break down the architecture, not in a dry, textbook way, but in the same way I understood it while building it. The Mental Model At a high level, this is what’s happening: The frontend behaves like an IDE The backend acts like a coordinator Workers actually run your code Redis connects everything S3 stores user solutions So let’s go step by step. Step 1: Writing Code (Frontend Sandbox) When you type