This is basically a full system design in one prompt and the scope is brutal.
Start by clarifying requirements and scale, then design a high-level architecture that separates read-heavy browsing from write-heavy purchase flows. Dive into the data model for events, venues, and seats, and explain how to handle concurrency, bursty traffic, and fraud with specific technologies and trade-offs. Emphasize consistency for seat ownership and discuss the waiting room as a load-shedding mechanism.
Pro tip: Proactively discuss trade-offs between strong and eventual consistency, and how you would handle failures (e.g., payment timeouts) to show production maturity. Also, mention that you would use a combination of techniques like optimistic locking and distributed locks, but be specific about where each is appropriate.
Ask about expected traffic (e.g., millions of concurrent users during on-sales), consistency needs, and key features. Define functional and non-functional requirements to scope the design.
Outline entities: events, venues, seats, users, orders, and payments. Choose appropriate databases (e.g., relational for transactions, NoSQL for catalog) and discuss indexing for search.
Design read-optimized services using caching, CDNs, and search engines (e.g., Elasticsearch). Explain how to handle high read throughput and keep data fresh.
Detail concurrency control (e.g., optimistic locking, distributed locks) to prevent overselling. Describe the purchase flow with payment integration, idempotency, and consistency guarantees.
Implement a waiting room with rate limiting and queueing (e.g., using Redis or Kafka). Discuss bot mitigation via CAPTCHAs, device fingerprinting, and anomaly detection.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.