FastAPI Real-Time Chat Application

This project is a real-time, multi-user chat application built with a FastAPI backend and a vanilla JavaScript frontend. The entire application is fully containerized with Docker, making it easy to run with a single command.

The backend uses WebSockets to manage persistent connections and broadcast messages instantly to all connected clients, demonstrating a modern, event-driven architecture.

✨ Key Features

• Real-Time Messaging: Uses WebSockets for instant, bi-directional communication.
• Connection Management: A central ConnectionManager on the server tracks all active users.
• System Broadcasts: Automatically announces when a user joins or leaves the chat.
• Chat Broadcasts: Messages sent by one user are immediately broadcast to all other users.
• Simple Frontend: A clean, single-page UI built with HTML, Tailwind CSS, and vanilla JavaScript.
• Fully Containerized: One-command setup using docker compose up --build.

🚀 Tech Stack

• Backend: FastAPI
• Server: Uvicorn
• Real-Time: WebSockets
• Frontend: HTML5, Tailwind CSS (via CDN), Vanilla JavaScript
• Containerization: Docker & Docker Compose
• Language: Python 3.10

🏁 Running the Project Locally

This project is fully containerized. The only prerequisite is having Docker and Docker Compose installed.

1. Clone the repository:

   git clone [https://github.com/bikilaketema/fastapi-chat-app.git](https://github.com/bikilaketema/fastapi-chat-app.git)
   cd fastapi-chat-app

2. Build and Run with Docker Compose: This single command will build the Python image, install dependencies, and start the uvicorn server.

   docker compose up --build

3. Open the Chat! Your application is now running. Open http://localhost:8000 in your browser to use the chat.

   To test the real-time functionality, open a second browser window (or tab) and go to the same address. Join with a different username and watch the messages appear in both windows instantly.