Amazon System Design

Design an e-commerce platform where users browse a large product catalog, search and filter listings, manage a persistent shopping cart, and place orders that decrement inventory in real time. In production this stack sits behind aggressive caching and search indexes; the product experience fails when search is slow, carts vanish on device switch, or two buyers claim the last unit.

You should support catalog and search, cart and checkout, order processing, inventory tracking, and personalized recommendations at scale. Be ready to explain how you prevent overselling under concurrent checkout, how you index and serve 100M+ products, how cart state survives sessions, and how you handle peak traffic without melting the database. Latency targets, consistency choices for inventory, and degradation when search lags are fair game.