Design transaction systems where every millisecond of downtime costs millions and accuracy is non-negotiable
Design Amazon-scale e-commerce with product catalog, cart, checkout, inventory management across warehouses, and Black Friday traffic handling.
Design a multi-tenant platform hosting millions of stores with custom themes, payment processing, and per-tenant isolation.
Design Stripe-like payment processing with PCI compliance, tokenization, multi-currency support, webhook delivery, and fraud detection.
Design a peer-to-peer payment system with balance management, transaction history, and instant transfers between users.
Design a three-sided marketplace connecting restaurants, drivers, and customers with real-time tracking, ETA prediction, and surge pricing.