Oddbean new post about login | logout Actually, in a way it is, it's not THE Nostr protocol but it is notes (messages) and (not really other stuff) transmitted by relays.
Media and files could count as other stuff which is transmitted via relays rather than being uploaded to a single webserver like what happens on Nostr. Here's an article if you want to learn more about SimpleX's file transfer protocol specially https://simplex.chat/blog/20230301-simplex-file-transfer-protocol.html