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README.md

Ticketmaster - Event Ticketing Platform

A full-stack event ticketing platform inspired by Ticketmaster, featuring seat selection, real-time availability, virtual waiting room for high-demand events, and time-limited checkout.

Codebase Stats

Metric Value
Total SLOC 8,535
Source Files 55
.ts 4,639
.md 1,754
.tsx 1,590
.sql 312
.json 137

Features

  • Event Browsing: Search and filter events by category, date, artist, and venue
  • Interactive Seat Selection: Visual seat map with real-time availability
  • Seat Reservation with Locking: Distributed seat locks using Redis prevent double-booking
  • Virtual Waiting Room: Fair queue system for high-demand events
  • Time-Limited Checkout: 10-minute hold on reserved seats with countdown timer
  • Order Management: View purchased tickets and order history

Architecture Highlights

  • Distributed Locking: Redis-based seat locks ensure no overselling
  • Optimistic Locking: Database transactions with FOR UPDATE NOWAIT for race condition prevention
  • Virtual Waiting Room: FIFO queue with configurable concurrent shopper limits
  • Real-time Updates: Short-TTL caching for seat availability during high traffic
  • Background Jobs: Automatic cleanup of expired holds

Tech Stack

Backend

  • Node.js + Express
  • PostgreSQL (primary data store)
  • Redis (session storage, distributed locks, queues)
  • TypeScript

Frontend

  • React 19 + TypeScript
  • Vite (build tool)
  • TanStack Router (routing)
  • Zustand (state management)
  • Tailwind CSS (styling)

Getting Started

Prerequisites

  • Node.js 18+
  • Docker and Docker Compose (for databases)
  • npm or yarn

Quick Start with Docker

  1. Clone and navigate to the project

    cd ticketmaster

  2. Start the databases

    docker-compose up -d

  3. Install backend dependencies

    cd backend
npm install

  4. Start the backend server

    npm run dev

    The API server will start on http://localhost:3001

  5. In a new terminal, install frontend dependencies

    cd frontend
npm install

  6. Start the frontend

    npm run dev

    The frontend will start on http://localhost:5173

Running Without Docker (Native Services)

If you prefer to run PostgreSQL and Redis natively:

  1. Install PostgreSQL and Redis

    • macOS: brew install postgresql redis
    • Ubuntu: sudo apt install postgresql redis-server

  2. Start the services

    # macOS with Homebrew
brew services start postgresql
brew services start redis

# Ubuntu
sudo systemctl start postgresql
sudo systemctl start redis-server

  3. Create the database

    createdb ticketmaster
psql ticketmaster -f backend/src/db/init.sql

  4. Set environment variables (optional)

    export DB_HOST=localhost
export DB_PORT=5432
export DB_USER=your_username
export DB_PASSWORD=your_password
export DB_NAME=ticketmaster
export REDIS_HOST=localhost
export REDIS_PORT=6379

  5. Start the backend and frontend as described above

Running Multiple Backend Instances

For testing load balancing and distributed behavior:

# Terminal 1 - Instance on port 3001
npm run dev:server1

# Terminal 2 - Instance on port 3002
npm run dev:server2

# Terminal 3 - Instance on port 3003
npm run dev:server3

API Endpoints

Authentication

  • POST /api/v1/auth/register - Register new user
  • POST /api/v1/auth/login - Login and create session
  • POST /api/v1/auth/logout - Logout and invalidate session
  • GET /api/v1/auth/me - Get current user

Events

  • GET /api/v1/events - List events (supports filtering)
  • GET /api/v1/events/:id - Get event details

Venues

  • GET /api/v1/venues - List all venues
  • GET /api/v1/venues/:id - Get venue details
  • GET /api/v1/venues/:id/sections - Get venue sections

Seats

  • GET /api/v1/seats/:eventId/availability - Get seat availability by section
  • GET /api/v1/seats/:eventId/sections/:section - Get individual seats in section
  • POST /api/v1/seats/:eventId/reserve - Reserve seats (creates 10-min hold)
  • POST /api/v1/seats/:eventId/release - Release held seats
  • GET /api/v1/seats/reservation - Get current reservation

Waiting Room

  • POST /api/v1/queue/:eventId/join - Join waiting room queue
  • GET /api/v1/queue/:eventId/status - Get queue position
  • POST /api/v1/queue/:eventId/leave - Leave queue
  • GET /api/v1/queue/:eventId/stats - Get queue statistics

Checkout

  • POST /api/v1/checkout - Complete purchase
  • GET /api/v1/checkout/orders - List user orders
  • GET /api/v1/checkout/orders/:id - Get order details
  • POST /api/v1/checkout/orders/:id/cancel - Cancel order

Sample Data

The database is seeded with:

  • 4 venues (Madison Square Garden, The O2 Arena, Staples Center, Red Rocks)
  • 6 sample events across different categories
  • Venue sections with VIP, Premium, Standard, and Economy pricing tiers
  • Admin user: admin@ticketmaster.local (for testing admin features)

Environment Variables

Backend

Variable Default Description
PORT 3001 Server port
DB_HOST localhost PostgreSQL host
DB_PORT 5432 PostgreSQL port
DB_USER ticketmaster PostgreSQL user
DB_PASSWORD ticketmaster_secret PostgreSQL password
DB_NAME ticketmaster PostgreSQL database
REDIS_HOST localhost Redis host
REDIS_PORT 6379 Redis port
CORS_ORIGIN http://localhost:5173 Allowed CORS origin

Frontend

Variable Default Description
VITE_API_URL /api API base URL (proxied in dev)

Testing the Flow

  1. Browse Events: Visit http://localhost:5173 to see available events
  2. Register/Login: Create an account or sign in
  3. Select Event: Click on an "On Sale" event
  4. High-Demand Event: For events with "High Demand" badge, enter the waiting room
  5. Select Seats: Choose a section, then click on available seats
  6. Reserve: Click "Reserve Seats" to create a 10-minute hold
  7. Checkout: Complete the purchase before the timer expires
  8. View Tickets: Go to "My Orders" to see purchased tickets

Development

# Backend
cd backend
npm run dev          # Start with hot reload
npm run build        # Build TypeScript
npm run lint         # Run ESLint
npm run type-check   # TypeScript type checking

# Frontend
cd frontend
npm run dev          # Start Vite dev server
npm run build        # Build for production
npm run lint         # Run ESLint
npm run type-check   # TypeScript type checking

Architecture Documentation

See architecture.md for detailed system design documentation.

See system-design-answer-fullstack.md for interview-style system design walkthrough.

Key Design Decisions

  1. Redis for Seat Locks: Sub-millisecond distributed locking with automatic expiry
  2. PostgreSQL FOR UPDATE NOWAIT: Prevents database-level race conditions
  3. 10-Minute Hold Duration: Balances user checkout time with seat turnover
  4. Virtual Waiting Room: Protects backend from traffic spikes, ensures fairness
  5. Session-Based Auth: Simple cookie + Redis sessions (no JWT complexity for learning)

Future Enhancements

  • Admin dashboard for event management
  • Payment integration (Stripe)
  • Email confirmation with tickets
  • Mobile ticket with QR codes
  • Secondary market (resale)
  • Bot detection and CAPTCHA
  • WebSocket for real-time seat updates

References & Inspiration