Here's a data flow:
http <--> nginx <--> uWSGI <--> python webapp
I guess there's http2uwsgi transfer in nginx, and uwsgi2http in uWSGI.
What if I want to directly call uWSGI to test an API in a webapp?
actually i'm using pyramid. just config [uwsgi] in .ini and run uWSGI. but i want to test if uWSGI hold webapp function normally, the uWSGI socket is not directly reachable by http.
First, consider those questions:

On which port is uWSGI running?
Is uWSGI running on your or on a remote machine?
If it's running on a remote machine, is the port accessible from your computer? (iptables rules might forbid external access)

If you made sure you have access, you can just call http://hostname:port/path/to/uWSGI for direct API access.
Can I use the uwsgi protocol to call http?