actix-web/examples/unix-socket/README.md

Unix domain socket example

$ curl --unix-socket /tmp/actix-uds.socket http://localhost/
Hello world!

Although this will only one thread for handling incoming connections according to the documentation.

And it does not delete the socket file (/tmp/actix-uds.socket) when stopping the server so it will fail to start next time you run it unless you delete the socket file manually.