LinkLens

A production-grade URL shortner built with FastAPI, PostgreSQL, and Redis.

Features

• JWT Authentication (register, login, refresh, logout)
• URL shortening with custom aliases and expiry
• Redis caching for fast redirects
• Async click tracking via background tasks
• Analytics — click summary, 7-day timeline, top referrers
• Collision-safe short code generation with retry logic
• Automatic cache fallback to PostgreSQL if Redis is unavailable
• Rate limiting per IP
• 18 automated tests

Architecture

graph TD
    Client -->|HTTP Request| FastAPI
    FastAPI -->|Check cache| Redis
    Redis -->|Cache hit| FastAPI
    FastAPI -->|Cache miss| PostgreSQL
    PostgreSQL -->|URL data| FastAPI
    FastAPI -->|302 Redirect| Client
    FastAPI -->|Background task| ClickTracker
    ClickTracker -->|Save click| PostgreSQL
    FastAPI -->|Token blacklist| Redis

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API Endpoints

Auth

Method	Endpoint	Description
POST	/api/v1/auth/register	Create account
POST	/api/v1/auth/login	Login, get tokens
POST	/api/v1/auth/refresh	Refresh access token
POST	/api/v1/auth/logout	Blacklist token

URLs

Method	Endpoint	Description
POST	/api/v1/urls/shorten	Create short URL
GET	/api/v1/urls	List my URLs
GET	/{short_code}	Redirect to original
DELETE	/api/v1/urls/{short_code}	Deactivate URL
PATCH	/api/v1/urls/{short_code}	Update alias/expiry

Analytics

Method	Endpoint	Description
GET	/api/v1/analytics/{short_code}/summary	Click summary
GET	/api/v1/analytics/{short_code}/timeline	Clicks per day
GET	/api/v1/analytics/{short_code}/referrers	Top referrers

Tech Stack

Layer	Technology
Backend	FastAPI
Database	PostgreSQL
Cache	Redis
Auth	JWT
ORM	SQLAlchemy
Migrations	Alembic
Testing	pytest + pytest-asyncio
Container	Docker
Deploy	AWS EC2