Design a High-Demand Event Ticket Marketplace
Company: Mercor
Role: Machine Learning Engineer
Category: System Design
Difficulty: medium
Interview Round: Onsite
Overview: Design a ticket marketplace that handles search, expiring holds, payment uncertainty, and extreme onsale spikes without overselling inventory. Reason about authoritative seat state, idempotent checkout, fenced expiry, waiting-room fairness, bot defenses, admission control, reconciliation, and failure testing.