FastAPI + Uvicorn: Basic Configuration for Local Development and Deployment

This article introduces the web development and deployment process using FastAPI with Uvicorn. FastAPI is a high-performance Python framework supporting asynchronous operations and automatic API documentation. Uvicorn, as an ASGI server, is the recommended deployment tool for FastAPI, and their combination enables efficient development. **Environment Installation**: First, create a virtual environment (e.g., `python -m venv venv`), activate it, and then install dependencies with `pip install fastapi uvicorn`. **Development Configuration**: Write `main.py`, define routes (e.g., root route `/` and parameterized route `/items/{item_id}`), and start the server with `uvicorn main:app --reload` for auto-reloading in development mode. Verify the interface by accessing `http://127.0.0.1:8000`. **Production Deployment**: Use the basic command `uvicorn main:app --host 0.0.0.0 --port 8000`. Specify the number of worker processes with `--workers` for multi-processing. Ensure the deployment server opens the port and manage processes via `nohup` or `systemd`. **Common Issues**: For port conflicts, change the port. If the service is unreachable, confirm `--host 0.0.0.0` and firewall settings. If installation fails, update pip or check Python version compatibility.