4. Event Ticketing System Design

🎟️ Overview
An event ticketing system allows users to browse events, purchase tickets, and manage bookings efficiently. Scalability, high availability, and accurate ticket inventory management are critical to ensure a seamless experience for both users and event organizers.

System Requirements

Functional Requirements

  1. Users should be able to browse events by categories, dates, and venues.
  2. Users should be able to search for specific events.
  3. Users should be able to view event details such as venue, performers, and seating arrangements.
  4. Users should be able to select and purchase tickets.
  5. Users should receive booking confirmations and e-tickets after successful purchases.

Non-Functional Requirements

  1. Availability: The system should be available at all times, especially during high-demand events.
  2. Consistency: Tickets should not be oversold. The system must guarantee strong consistency when booking tickets.
  3. Scalability: The system should scale to accommodate thousands of concurrent users during peak traffic (e.g., concert sales).
  4. Security: Secure payment processing and data protection measures for users’ personal and financial information.
  5. Performance: The system should handle search and booking requests with minimal latency (<500ms).

Core System Components

  1. Event Management Service: Handles creating and managing event details, including schedules, performers, and venues.
  2. Search & Discovery Service: Enables users to search for events by criteria such as location, performer, or date.
  3. Ticket Inventory Service: Manages real-time ticket availability and seat selection.
  4. Booking Service: Handles ticket reservations and ensures transactional integrity when purchasing tickets.
  5. Payment Gateway Integration: Connects to third-party payment processors like Stripe or PayPal to handle payment transactions.
  6. Notification Service: Sends booking confirmations, updates, and ticket information via email or SMS.

API Endpoints

  1. Browse Events
    GET /events
    Fetches a list of upcoming events. Supports filtering by date, category, and location.
    Query Parameters:
    • category (optional): Filters events by category (e.g., concerts, sports).
    • startDate and endDate: Filters events by a date range.
    • location: Filters events based on location.
  2. View Event Details
    GET /events/:eventId
    Returns detailed information about a specific event, including venue details and available tickets.
    Path Parameters:
    • eventId: The unique identifier of the event.

  3. Search Events
    GET /search?query={keyword}
    Searches for events based on keywords (e.g., performer name, event title).

  4. Check Ticket Availability
    GET /events/:eventId/tickets
    Returns the available ticket inventory for a specific event.
    Path Parameters:
    • eventId: The unique identifier of the event.
  5. Book Tickets
    POST /bookings
    Books tickets for a specified event.
    Request Body:
    • eventId: The ID of the event being booked.
    • ticketIds: A list of ticket IDs to reserve.
    • paymentInfo: Payment details (e.g., credit card info or tokenized payment data).

Database Design

Core Entities

  1. Event: Stores the basic information about an event, such as the event name, date, time, venue, and performer(s).
  2. Venue: Stores details about the event venue, including seating layout and capacity.
  3. Ticket: Represents an individual ticket, including its seat, price, and status (available, reserved, sold).
  4. Booking: Represents a reservation made by a user for one or more tickets to an event.
  5. User: Represents the customers purchasing tickets, including their personal information and booking history.

Database Tables

  1. Events Table
    • event_id: Primary key.
    • name: Name of the event.
    • date: Date and time of the event.
    • venue_id: Foreign key to the venue table.
  2. Venues Table
    • venue_id: Primary key.
    • name: Name of the venue.
    • location: Venue address.
    • capacity: Total seating capacity.
  3. Tickets Table
    • ticket_id: Primary key.
    • event_id: Foreign key to the event.
    • seat_number: Seat designation (row and seat number).
    • price: Price of the ticket.
    • status: Status of the ticket (available, reserved, sold).
  4. Bookings Table
    • booking_id: Primary key.
    • user_id: Foreign key to the user table.
    • event_id: Foreign key to the event.
    • total_price: Total price of the booked tickets.
    • payment_status: Payment status (pending, confirmed, failed).
    • created_at: Timestamp of when the booking was made.

Scalability Considerations

Microservices Architecture

Breaking down the system into microservices ensures each service can scale independently, particularly for high-traffic components like the search and booking services.

Load Balancing

A load balancer will distribute incoming requests across multiple instances of the search, event, and booking services to prevent bottlenecks and ensure availability.

Caching

Using caching mechanisms (e.g., Redis) for frequently accessed data like event details and ticket availability will reduce database load and improve response times for users.

Database Sharding

To handle the high volume of ticketing transactions, we can shard the ticket and booking databases by event_id. This reduces contention on the database and ensures faster read and write operations.

Message Queues for Booking

Incorporate message queues (e.g., RabbitMQ or Kafka) for processing bookings. When a user books a ticket, the booking request is added to the queue, ensuring it is processed sequentially and preventing double bookings.

System Resilience

Data Consistency

To prevent double bookings, the system ensures strong consistency using database transactions during the booking process. This guarantees that no two users can book the same seat simultaneously.

Eventual Consistency for Read Operations

The system can leverage eventual consistency for read-heavy operations such as searching for events or viewing event details. This allows us to scale the system without compromising user experience.

Redundancy & Failover

Set up redundant servers and data replication across multiple data centers to ensure system availability, even during partial outages.

Conclusion

The Event Ticketing System Design focuses on handling high traffic during peak ticket sales, ensuring availability, and preventing double bookings. By leveraging a microservices architecture, load balancing, caching, and database sharding, the system is scalable and can provide a seamless user experience.