What is Uvicorn?

Uvicorn is an ASGI (Asynchronous Server Gateway Interface) server implementation using uvloop and httptools for high performance. It serves modern async Python frameworks like FastAPI, Starlette, and Django (async views). Uvicorn supports HTTP/1.1, WebSockets, and can handle thousands of concurrent connections efficiently. In production, it is typically run behind Gunicorn using Uvicorn workers (gunicorn -k uvicorn.workers.UvicornWorker) for process management and graceful restarts. Configuration includes host/port binding, SSL certificates, log levels, and worker count. It replaces WSGI servers like Gunicorn's default worker for async applications.