URL Shortener Service

A scalable URL shortener service built with TypeScript and Clean Architecture principles.

Features

• Create shortened URLs
• Custom alias support (up to 16 characters)
• Click tracking and analytics
• RESTful API with Swagger documentation
• In-memory SQLite database
• Clean Architecture implementation
• CQRS pattern
• Comprehensive test coverage

Architecture

The project follows Clean Architecture principles with the following layers:

• Core: Contains entities and repository interfaces
• Application: Implements use cases (commands and queries)
• Infrastructure: Contains concrete implementations (database, external services)
• API: Handles HTTP routes and controllers

API Endpoints

• POST /api/urls: Create a new shortened URL
• GET /:shortCode: Redirect to original URL
• GET /api/urls/most-clicked: Get most clicked URLs

Getting Started

1. Install dependencies:

   npm install

2. Start the development server:

   npm run dev

3. View API documentation: Open http://localhost:3000/documentation

Testing

Run the test suite:

npm test

Design Decisions

1. Clean Architecture: Ensures separation of concerns and maintainability
2. CQRS Pattern: Separates read and write operations
3. In-memory SQLite: Fast and reliable for development/testing
4. Fastify: High-performance web framework
5. Zod: Runtime validation for request payloads
6. nanoid: Generates unique, URL-safe identifiers

Performance Considerations

• In-memory database for fast access
• Efficient URL lookup using indexes
• Minimal dependencies
• Request validation at the edge