FastAPI and ASGI on HostRight

FastAPI compatibility

FastAPI is an ASGI framework. HostRight's HostRight Control Panel Python application interface currently expects WSGI applications through Phusion Passenger. A direct uvicorn or hypercorn process is not the same as a standard HostRight Python application.

For Django, Flask, Pyramid, Bottle, and custom WSGI projects, use the Python deployment guide.

Before choosing an adapter

An ASGI-to-WSGI adapter may allow a limited FastAPI application to run through a WSGI interface, but it can change or remove async behavior, streaming behavior, WebSockets, and performance characteristics. Test the complete application before relying on it.

FastAPI applications that need WebSockets, long-lived connections, async background work, or high concurrency should be reviewed with HostRight support before production deployment.

If you test a WSGI adapter

Keep the project private and configure HostRight Control Panel with:

Application root: apps/example-fastapi
Application startup file: passenger_wsgi.py
Application entry point: application

The startup file must expose a WSGI callable created by the adapter. The exact adapter and setup depend on the FastAPI version and project structure. Do not guess the import path from a Flask example.

Test:

python -c "import passenger_wsgi; print(passenger_wsgi.application)"
curl -I https://example.com

If the project requires a native ASGI server, use a hosting architecture that supports that process model or contact support for an approved deployment path.