I'm using the latest version of tower-http (0.4.4) and following the same approach as in the main example
Router::new().nest_service("/assets", ServeDir::new("assets"));
Everything runs smoothly in development, but I don't understand why when I deploy it to Debian Linux, the static file URLs result in a 404 error
Serving static files
Did you also deploy the /assets directory to production in the same directory as the Rust binary? It still needs the files available to server them, they aren't compiled into your binary.