Design Ticketmaster

Design a Ticketmaster-style online event-ticketing platform that lets millions of users browse events, view interactive seat maps, reserve seats for a short time window, and complete payment to obtain tickets. The system must never double-book a seat, must gracefully handle traffic spikes (e.g., 100 000+ concurrent users during a Taylor Swift on-sale), and must provide fair ordering when demand far exceeds supply. Scope the full consumer-facing flow: search & discovery, seat selection & temporary hold (TTL ≈ 5–10 min), payment via an external processor, and final ticket issuance with QR codes. Out of scope for the initial design: admin tooling, dynamic pricing, transfers/resales, and post-purchase customer service.