How We Built an EdTech Platform That Scaled to 250K Daily Users

In 18 months, we took an EdTech platform from a founder's wireframe to 250,000 daily active users. The app handles 2,000+ concurrent video streams, processes 50,000 quiz submissions per hour, and runs on a $4,200/month infrastructure bill. Here's what we built, what broke, and what we'd do differently. The Problem We Were Solving The founder wanted CA exam preparation for 500K+ students. Existing platforms were either expensive (Unacademy at $200+/year) or had poor UX. The brief: live classes, recorded lectures, AI-powered quizzes, and doubt resolution — all at a $50/year price point. Budget: $40K for MVP. Timeline: 12 weeks. The Architecture That Made It Work We didn't overthink the stack. We picked proven tools and focused on shipping. Frontend: Flutter with BLoC state management. One codebase for iOS and Android saved us 40% compared to building native. Backend: Node.js + Express for the API server. Python FastAPI for the quiz engine and ML-powered adaptive learning. Database: Postg