Advanced URL Shortener Backend

Welcome to the backend repository for the Advanced URL Shortener project! This API offers robust URL shortening capabilities, including user authentication, detailed analytics, and essential security features like rate limiting and caching. The goal is to deliver a scalable, efficient service that simplifies URL sharing while offering valuable insights into link performance.

Features

This backend API powers the core logic of the URL shortener:

• Google Sign-In Authentication Secure authentication via Google Sign-In for a smooth and trusted login experience.

• ** URL Shortening API** (POST /api/shorten)

  • Convert long URLs into short, memorable ones
  • Supports optional custom aliases
  • Group links by topic (e.g., acquisition, marketing) for organized analytics
  • Includes rate limiting to prevent abuse

• ** Smart Redirects** (GET /:alias)

  • Redirects to the original URL when a short link is accessed
  • Captures analytics: timestamp, user agent, IP, geolocation, OS, device

• Analytics APIs

  • Specific URL Analytics: GET /api/analytics/:alias
  • Topic-Based Analytics: GET /api/analytics/topic/:topic
  • Overall Analytics: GET /api/analytics/overall

• ** Caching with Redis**

  • Accelerates performance by caching both redirects and analytics data

• ** API Documentation**

  • Complete Swagger/OpenAPI documentation for all endpoints

Technologies Used

• Node.js & Express.js – Backend framework
• MongoDB + Mongoose – NoSQL database
• Redis – Caching layer
• Passport.js (Google OAuth) – User authentication
• express-session + connect-mongo – Session management
• express-rate-limit – API rate limiting
• Swagger (swagger-jsdoc & swagger-ui-express) – API documentation
• dotenv – Environment variable management

🛠️ Getting Started (Local Development)

1. Clone the Repository

   git clone https://github.com/KulkarniShrinivas/Advanced-URL-Shortener_App.git
   cd Advanced-URL-Shortener_App

2. Install Dependencies

   npm install

3. Configure Environment Variables

   Create a .env file with the following:

   PORT=5000
   MONGO_URI=your_mongo_uri
   GOOGLE_CLIENT_ID=your_google_client_id
   GOOGLE_CLIENT_SECRET=your_google_client_secret
   REDIS_HOST=localhost
   REDIS_PORT=6379
   SESSION_SECRET=your_secure_session_secret
   GOOGLE_CALLBACK_URL=http://localhost:5000/api/auth/google/callback

   Notes:

   • Set up a Google OAuth2.0 client in the Google Cloud Console
   • Make sure MongoDB Atlas allows your IP
   • Ensure Redis is running locally or through Docker

4. Run the Backend

   npm start
   # or
   npm run dev

   Visit: http://localhost:5000

Deployment

• Live Backend: https://advanced-url-shortener-app-gpx2.onrender.com

• Environment Variables: Same as local .env, configured via Render's environment settings

• Google OAuth Redirect URI for Production:

  https://advanced-url-shortener-app-gpx2.onrender.com/api/auth/google/callback
  

• CORS Configuration: Currently set to * for testing. In production, restrict to your frontend domain (e.g., https://your-frontend.netlify.app).

📚 API Documentation

• Local: http://localhost:5000/api-docs
• Live: https://advanced-url-shortener-app-gpx2.onrender.com/api-docs

📐 Architecture & Design Decisions

• Modular Codebase – Routes, controllers, models, middlewares, and configs separated for maintainability
• Authentication – Google Sign-In via Passport.js; sessions stored securely in MongoDB
• Rate Limiting – Express-rate-limit with IP-based keying for abuse prevention
• URL Analytics – Tracked per redirect and grouped by topic or user
• Redis Caching – Boosts performance for frequently accessed data
• Swagger Docs – Developer-friendly API interface

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