Ticketing System (Ticketmaster)
Difficulty: Medium
What It Tests
Inventory management, concurrent seat reservation, preventing double-booking under high load.
Topics Covered
- Distributed Locking
- Caching
- Database Design: SQL vs NoSQL
- API Design
- CAP Theorem & Consistency Models
Hello Interview Breakdown
Read the full Hello Interview breakdown →
Approach Hints
- Use optimistic locking (row version check) or SELECT FOR UPDATE to prevent race conditions
- Temporarily reserve seats in Redis with a TTL
- Finalize payment before confirming reservation
- Use a queue for high-demand events to serialize requests