Like other Tor-based apps like OnionShare or Ricochet, Tor gives us a nice overlay network where every onion address is permanent (it's just a keypair) and NAT traversal is taken care of. So you get an invite link with a few addresses in it and you sync others.

We're also working on an optional server to support notifications on iOS where apps cannot run in the background enough to be useful. We expect a lot of people will use this to improve performance on other platforms too, but you won't need to.

Quiet is still not ready for daily use yet, and not audited, but we're serious about making it useful to small workplace teams and activist orgs that need something between Slack and Signal.