I don't think you read the docs or looked at the code. Joinstr is a protocol. I have built CLI, web app and electrum plugin as clients to use it. CLI and web app use full node.

You can create your own app that follows the same protocol if you don't like one of these. I am presently working on electrum plugin because I am the only contributor. Even electrum plugin can be used with own electrum personal server for better privacy.

Join telegram group to discuss more: https://t.me/joinstr