This is an extremely simple, dependency free example of how Rust can be used as a backend/API in web development.
The server listens to requests on port 8080 and simply logs the number of requests from each client IP address, and then returns the number of requests as a JSON object {"requests": 2}.
That's all it does.
To test it out:
cargo run --release
And then open index.html in your favorite web browser
Or, you can use docker to spawn a container running Nginx that will proxy requests to the rust backend
docker build -t rust-backend .
docker run -d -p 80:80 rust-backend
At then go to http://localhost in your browser.