Ticketmaster / BookMyShow — Notes

Functional

• Browse events, view seat map, hold, pay, get ticket.
• Wait-list, refund, resale.
• Anti-bot, fair queueing for hot drops.

Non-functional

• Strict no-double-booking.
• Survive flash crowds (10–100× normal traffic) for marquee events.
• p99 hold response < 1 s under load.

Capacity

• Big drop: 500k+ concurrent users in queue.
• Seat catalog: 100k+ seats for a stadium.

Schema

• events(id, venue_id, time, status)
• shows(id, event_id, hall, sale_start)
• seats(show_id, seat_id, state, held_by, held_until, version)
• bookings(id, user_id, show_id, seat_ids[], payment_id, status, idempotency_key)

Trade-offs

• Strong consistency on seats non-negotiable; pay the latency.
• TTL holds prevent permanent leaks but require sweepers.
• Virtual queue is mandatory for big drops or service melts down.
• Resale complicates ticket identity → unique IDs, key rotation per transfer.

Refs

• Ticketmaster engineering "Verified Fan" posts.
• BookMyShow architecture talks.
• ByteByteGo "Design ticketing", Alex Xu Vol 2.