It’s a messaging app.

There’s only one way to add a contact. They either show you a QR code or they send you … there’s TWO ways to add a contact: They show you a QR code, send you a one time link or have a long-lived… there’s THREE ways to add a contact: You either show someone a one time QR code, send them a one time link or have a long-lived link to be added somewhere.

The server(s) defaults to a centralised service but you can host your own server too, if you want.