A Spring Boot URL Shortener application with Redis caching, MySQL persistence, Flyway database migrations, rate limiting, and click analytics.

This project converts long URLs into short, shareable links. It also tracks redirects, stores click data, applies rate limiting, and uses Redis for fast access.

The goal of this project is to showcase backend engineering practices commonly used in modern Java applications.

• 🔗 Shorten long URLs into compact short codes
• ✍️ Support custom aliases
• ↪️ Redirect short URLs to the original destination
• 📊 Track click count and click analytics
• 🚦 Redis-based rate limiting
• ⚡ Cache original URLs in Redis for fast redirects
• 🗄️ Persist URLs and click events in MySQL
• 🔄 Manage database schema with Flyway
• 🐳 Containerized with Docker and Docker Compose

1. User sends a long URL to the shorten endpoint.
2. Application generates a unique short code.
3. URL data is stored in MySQL.
4. Original URL is cached in Redis.
5. User opens the short URL.
6. Application checks Redis first.
7. If found, the user is redirected immediately.
8. Click event is stored for analytics.

src
├── main
│   ├── java
│   │   └── com.ragul.UrlShortener
│   │       ├── config
│   │       ├── controller
│   │       ├── dto
│   │       ├── model
│   │       ├── repository
│   │       ├── service
│   │       ├── exception
│   │       └── util
│   │
│   └── resources
│       ├── application.yml
│       └── db
│           └── migration
│
└── test

{
  "originalUrl": "https://example.com/articles/spring-boot",
  "customAlias": "spring",
  "expiresAt": "2026-12-31T23:59:59"
}

{
  "shortUrl": "http://localhost:8080/api/spring",
  "shortCode": "spring",
  "originalUrl": "https://example.com/articles/spring-boot",
  "createdAt": "2026-08-01T10:30:00",
  "expiresAt": "2026-12-31T23:59:59"
}

Configure your environment variables:

DB_URL=jdbc:mysql://localhost:3306/url_shortener
DB_USERNAME=root
DB_PASSWORD=password
REDIS_HOST=localhost
REDIS_PORT=6379

Never commit your .env file. Use .env.example instead.

server:
  port: 8080

spring:
  application:
    name: UrlShortener

  datasource:
    url: ${DB_URL}
    username: ${DB_USERNAME}
    password: ${DB_PASSWORD}

  jpa:
    hibernate:
      ddl-auto: validate
    show-sql: true

  flyway:
    enabled: true
    locations: classpath:db/migration
    baseline-on-migrate: true

  data:
    redis:
      host: ${REDIS_HOST}
      port: ${REDIS_PORT}
      timeout: 2000ms

url-shortener:
  base-url: http://localhost:8080
  short-code:
    length: 6
    max-attempts: 10
  rate-limit:
    max-requests-per-minute: 2
    max-requests-per-hour: 10
    minute-window: 1m
    hour-window: 1h
  cache:
    ttl-minutes: 30

git clone https://github.com/<your-username>/UrlShortener.git
cd UrlShortener

Make sure both services are running.

./mvnw spring-boot:run

or

mvn spring-boot:run

Build and start all services

docker compose up --build

Run in detached mode

docker compose up -d

Stop containers

docker compose down

Flyway automatically creates and manages the database schema.

Main Tables

• url_data
• click_events

• Add authentication and user-specific URL management
• QR code generation
• Add Swagger/OpenAPI documentation
• Add unit and integration tests
• Add a dashboard UI for analytics
• Add custom domain support
• Monitoring with Prometheus & Grafana

Contributions, suggestions, and improvements are welcome.

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Open a Pull Request

This project is licensed under the MIT License.