Design Ticketmaster
HardSystem design · Inventory and Concurrency
Design Ticketmaster. Users search events, browse a seat map, hold seats for a few minutes, and pay. A hot on-sale has ~500K users hitting a 50K-seat venue at the same minute. Guarantee no double-booking, run a fair waiting room, expire holds, handle payment failure and rollback, and resist bots and resellers. Out of scope: resale marketplace, dynamic pricing, and venue/artist onboarding.
Requirements
- Prevent double booking and overselling seats
- Support short-lived seat holds and payment expiration
- Handle extreme traffic spikes and queue waiting rooms
- Discuss inventory consistency, locks, queues, fraud, and payment rollback