🔐 JWT Authentication System using Flask

A secure, production-ready token-based authentication backend built with Flask and JWT. This system implements industry-standard security practices for user registration, login validation, and protected API routes.

🌟 Features

• 🔒 Secure User Registration - Password hashing with bcrypt
• 🎫 Token-Based Authentication - JWT token generation and validation
• 🛡️ Protected API Routes - Bearer token authorization
• 👤 User Login System - Credential validation and session management
• 💾 Database Persistence - SQLite with SQLAlchemy ORM
• 🚀 RESTful API - Clean and standardized endpoints

🛠️ Tech Stack

Backend

• Python - Core programming language
• Flask - Lightweight REST API framework

Authentication & Security

• JWT (JSON Web Token) - Stateless token-based authentication
• Flask-JWT / PyJWT - Token encoding and decoding
• bcrypt / Flask-Bcrypt - Password hashing algorithm

Database

• SQLite - Embedded database for user storage
• SQLAlchemy - Object-Relational Mapping (ORM)

📋 API Endpoints

Method	Endpoint	Description	Authentication
POST	/register	Create new user account	❌ Public
POST	/login	Authenticate and get JWT token	❌ Public
GET	/profile	Get user profile information	✅ Required

🚀 Getting Started

Prerequisites

• Python 3.8+
• pip package manager

Installation

1. Clone the repository

git clone https://github.com/ares-coding/jwt-authentication-flask.git
cd jwt-authentication-flask

2. Create virtual environment

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

3. Install dependencies

pip install -r requirements.txt

4. Set environment variables

export SECRET_KEY='your-secret-key-here'
export DATABASE_URL='sqlite:///users.db'

5. Run the application

python app.py

The API will be available at http://localhost:5000

📝 Usage Examples

1. Register a New User

curl -X POST http://localhost:5000/register \
  -H "Content-Type: application/json" \
  -d '{
    "username": "john_doe",
    "email": "john@example.com",
    "password": "SecurePass123!"
  }'

Response:

{
  "message": "User registered successfully",
  "user_id": 1
}

2. Login and Get JWT Token

curl -X POST http://localhost:5000/login \
  -H "Content-Type: application/json" \
  -d '{
    "username": "john_doe",
    "password": "SecurePass123!"
  }'

Response:

{
  "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "token_type": "Bearer",
  "expires_in": 3600
}

3. Access Protected Route

curl -X GET http://localhost:5000/profile \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."

Response:

{
  "user_id": 1,
  "username": "john_doe",
  "email": "john@example.com",
  "created_at": "2024-02-16T10:30:00Z"
}

🔒 Security Features

• Password Hashing: All passwords are hashed using bcrypt with salt rounds
• JWT Tokens: Stateless authentication with configurable expiration
• Bearer Token Authorization: Industry-standard HTTP authentication
• SQL Injection Protection: SQLAlchemy ORM prevents SQL injection attacks
• Input Validation: Server-side validation for all user inputs

📂 Project Structure

jwt-authentication-flask/
├── app.py                 # Main application file
├── models.py              # Database models
├── auth.py                # Authentication logic
├── config.py              # Configuration settings
├── requirements.txt       # Python dependencies
├── README.md             # Project documentation
└── users.db              # SQLite database (generated)

🧪 Testing

Run the test suite:

python -m pytest tests/

📦 Dependencies

Flask==2.3.0
Flask-SQLAlchemy==3.0.0
Flask-Bcrypt==1.0.1
PyJWT==2.8.0
python-dotenv==1.0.0

🤝 Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📄 License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

👨‍💻 Author

Au.dev

• GitHub: @ares-coding

Acknowledgments

• Flask documentation and community
• JWT.io for JWT standards
• bcrypt library maintainers

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