FastAPI URL Shortener API

A simple URL shortener service built with FastAPI and SQLAlchemy.
This project demonstrates how to create a secure, database-backed URL shortener with user registration and login functionality.

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-Live Url: https://urlapi-r5yr.onrender.com/

-Documentation Link: https://urlapi-r5yr.onrender.com/docs

Features

• User registration and login
• JWT-based authentication (optional to add)
• Create shortened URLs with unique codes
• Redirect from short URL to original URL
• Track number of clicks on each shortened URL
• SQLite database integration using SQLAlchemy ORM
• CORS middleware enabled for frontend interaction

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Tech Stack

• FastAPI - Web framework
• SQLAlchemy - ORM for database operations
• SQLite - Lightweight database (can be swapped for MySQL/PostgreSQL)
• Pydantic - Data validation and serialization
• Python 3.9+

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Getting Started

Prerequisites

• Python 3.9 or newer installed
• pip package manager

Installation

1. Clone the repository

git clone https://github.com/your-username/fastapi-url-shortener.git
cd fastapi-url-shortener 

2. Create and Activate Virtual Environment

python -m venv .venv
source .venv/bin/activate  # Linux/macOS
.venv\Scripts\activate     # Windows

3. Install dependencies

pip install -r requirements.txt

4. Run the application

uvicorn main:app --reload

🌐 Frontend Interface

A basic frontend is provided inside the frontend/ folder to interact with the API:

📂 frontend/index.html

Login and register forms

Stores JWT access token in sessionStorage

📂 frontend/shorten.html

Allows authenticated users to shorten URLs

Displays shortened URL

Preserves last shortened result using sessionStorage

Redirects to login page if user is not authenticated

To test the frontend:

Open frontend/index.html in your browser to register or login

Once logged in, navigate to frontend/shorten.html to shorten URLs

💡 Make sure your backend is running at http://127.0.0.1:8000 Use Live Server extension in VSCode for better local dev

API END POINT

Method	Endpoint	Description	Auth
POST	/register	Register a new user	❌
POST	/login	Login a user	❌
POST	/shorten	Create a shortened URL	✅
GET	/get_all	Get all shortened URLs (for debug)	❌
GET	/{url_code}	Redirect to original URL	❌

🔐 Register a new user

POST /register

{
  "names": "John Doe",
  "email": "john@example.com",
  "password": "StrongPassword123"
}

🔑 Login user

POST /login

{
  "email": "john@example.com",
  "password": "StrongPassword123"
}

Returns:

{
    "status": 200,
    "message": "User logged in",
    "access_token":"................"
}

🔗 Shorten a URL

POST /shorten

{
  "valid": "https://www.example.com"
}

Return:

{
    "message": "URL shortened well",
    "shorten_url": "http://127.0.0.1:8000/RprNAa68",
    "data": {
        "valid": "https://github.com",
        "code": "RprNAa68",
        "created_at": "2000-00-12T13:17:55.436658",
        "clicks": 0,
        "id": "70d8c8ab-6d5c-4b07-b2c2-e79a7668e2ab",
        "expires_at": null
    }
}

↪️ Redirect using short code

GET /{url_code}

Example: GET /abc123xy Redirects to original URL.

PROJECT STRUCTURE

.
├── main.py              # FastAPI app and routes
├── models.py            # Pydantic & SQLAlchemy models
├── demo.py              # Code generator and utility functions
├── requirements.txt     # Python dependencies
├── README.md            # Project documentation
├── db/
│   ├── database.py      # SQLAlchemy DB setup
│   └── models.py        # SQLAlchemy models
├── frontend/
│   ├── index.html       # Login & Register page
│   └── shorten.html     # URL shortening interface