Ticket Master (Event Ticketing System)¶

Quick Reference Guide for System Design Interviews

Problem Statement¶

Design an event ticketing system like Ticketmaster that handles high-traffic ticket sales, prevents overselling, manages seat selection, and handles flash sales for popular events.

Requirements¶

Functional Requirements¶

Browse and search events
View venue seating map
Select and reserve seats
Complete purchase within time limit
Prevent double-booking
Support waitlists

Non-Functional Requirements¶

Availability: 99.99%
Consistency: Strong (no overselling)
Latency: < 200ms for seat availability
Scale: 100K concurrent users per event
Fairness: First-come-first-served

Key Challenges¶

Key Challenges

High-Level Architecture¶

High-Level Architecture

Seat Inventory Management¶

Seat Inventory Model

Database Schema:

CREATE TABLE seats (
    event_id       UUID,
    seat_id        VARCHAR(20),  -- 'A-1', 'B-15'
    section        VARCHAR(20),
    row            VARCHAR(10),
    seat_number    INT,
    price_tier     VARCHAR(20),
    price          DECIMAL(10,2),
    status         ENUM('available','reserved','sold'),
    reserved_by    UUID,
    reserved_at    TIMESTAMP,
    version        INT,  -- Optimistic locking
    PRIMARY KEY (event_id, seat_id)
);