Capstone: a food delivery order system, Weeks 1 to 6

A full 45-minute interview that uses every week so far: clarify a 5 million order a day platform, estimate 230 orders, 7,000 writes and 60,000 reads a second at peak, sketch an event-driven architecture, then deep-dive into an outbox with stable order IDs, idempotent Stripe payments, race-free driver assignment, an order saga with compensation, Redis GEO location tracking, rate limits and backpressure, and finish with 10x scaling, edge cases, monitoring, and what to build first.