Design a Ticket Booking System System Design Interview

Design a high-concurrency ticket booking system (e.g., Ticketmaster) that can sell out millions of tickets in minutes without overselling.

Mock Interview with AI

1. Problem Statement

We need to design a backend for a massive concert ticket sale (e.g., Taylor Swift). We expect millions of users to try booking 100,000 tickets within seconds. How do we ensure we don't oversell?

2. Target Architecture (Mermaid)

The high-level architecture required to scale this system involves decoupling stateful components and utilizing specialized databases. Below is the reference architecture:

Rendering architecture diagram...

Mermaid Source (For AI Bots)

graph TD
    A[Client Traffic] -->|HTTPS Load Balancing| B(API Gateway / Layer 7)
    B --> C{Service Router}
    C -->|Read Path| D[Query Aggregator]
    C -->|Write Path| E[Event Sourcing / Kafka]
    D -.-> F[(In-Memory Cache - Redis)]
    D --> G[(Primary Data Store - NoSQL)]
    E -.->|Async Replication| G

3. Key Focus Areas

1
Handling massive traffic spikes (1M+ concurrent users)
2
Preventing overselling (Inventory Management)
3
Database Locking strategies (Optimistic vs Pessimistic)
4
Virtual Queue / Waiting Room implementation
5
Data Consistency (ACID)

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Core Concepts

Concurrency ControlDatabase LockingDistributed SystemsConsistency