FastApi mini-chat: Modern interface, websockets and SQLAlchemy

This project is a simple real-time chat application with user registration, authentication, message storage, and a basic web interface. It is built for learning purposes but is deployable without major rewrites.

🧰 Tech Stack

• Backend: FastAPI (Python)

• Database: SQLAlchemy + aiosqlite (async SQLite)

• Migrations: Alembic (async setup)

• Authentication: JWT tokens + password hashing (bcrypt / passlib)

• Real-time communication: WebSockets

• Frontend: HTML, CSS, Vanilla JavaScript

📦 Project Structure

project_root/
│
├── app/
│   ├── database.py          # Database connection and base model
│   ├── config.py            # App configuration (.env reader)
│   ├── main.py              # App entry point
│   │
│   ├── users/               # User logic
│   │   ├── models.py        # User model
│   │   ├── dao.py           # Data access logic
│   │   ├── auth.py          # Auth logic (JWT, hashing, login/register)
│   │   ├── dependencies.py # Current user dependency
│   │   └── schemas.py      # Pydantic schemas
│   │
│   ├── chat/                # Chat logic
│   │   ├── models.py        # Message model
│   │   ├── dao.py           # Message DAO
│   │   ├── router.py       # Routes and WebSocket handlers
│   │   └── schemas.py      # Pydantic schemas for messages
│   │
│   ├── static/              # Frontend static files
│   │   ├── js/
│   │   │   ├── auth.js
│   │   │   └── chat.js
│   │   └── styles/
│   │       ├── auth.css
│   │       └── chat.css
│   │
│   └── templates/           # HTML templates
│       ├── auth.html        # Login / registration page
│       └── chat.html        # Chat page
│
├── .env                     # Environment variables
├── pyproject.toml         # Python dependencies
└── other project files

🚀 How to Run

• Clone the repository.
• Install dependencies
• Create a .env file like in .env.example
• Run database migrations:

alembic revision --autogenerate -m "Initial revision"
alembic upgrade head

This will create the SQLite database with all required tables.

• Start the application: uvicorn app.main:app --reload

• Open in browser: http://127.0.0.1:8000 You will see the authentication page. After logging in, you are redirected to the chat.

✅ Features

• User registration and login

• Secure password hashing

• JWT authentication with cookies

• Real-time messaging via WebSockets

• Message storage in SQLite

• Simple web interface (no frontend frameworks)

• Ready for deployment with minimal changes

🔧 What Can Be Improved

• File and media message support

• Online status and typing indicators

• Better UI/UX

• Replace SQLite with PostgreSQL for production

• User roles and permissions

• Tests, CI/CD

• Docker support

Right now this is a solid demo project, not a production-grade messenger. It does its job without pretending to be Telegram.

📄 License

No license specified by default. If you plan to use this publicly, add one (MIT is the usual painless choice).