Can Nginx be used as a server for FastAPI? Can it replace Uvicorn?

Nginx can be used as a reverse proxy server in front of a FastAPI application, which is typically run on Uvicorn or Gunicorn. Nginx does not replace Uvicorn, as Uvicorn is an ASGI server that directly handles requests to FastAPI and executes asynchronous Python code.

The role of Nginx is to accept HTTP requests from clients, perform load balancing, SSL termination, caching, and proxy requests to Uvicorn. Thus, Nginx and Uvicorn work together and are not interchangeable.

Example Nginx configuration for proxying to Uvicorn:

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://127.0.0.1:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}