FastAPI 0.115: Running the app

Start the development server

Run the app with auto-reload. It listens on 127.0.0.1:8000 by default.

fastapi dev main.py

Change the host and port

Listen on all interfaces on port 8080, for example inside a container or on a LAN.

fastapi dev main.py --host 0.0.0.0 --port 8080

Caution: Binding to 0.0.0.0 exposes the development server to your network.

Start the production server

Run without auto-reload, listening on 0.0.0.0 by default.

fastapi run main.py

Run several worker processes

Start multiple processes to use more than one CPU core.

fastapi run main.py --workers 4

Run with Uvicorn directly

Start the app object named app in main.py with auto-reload.

uvicorn main:app --reload

Fetch the OpenAPI schema

Download the JSON schema FastAPI generates. The interactive docs are served at /docs.

curl http://127.0.0.1:8000/openapi.json