Naven
Answers
How do you find somebody on Naven?
By their email address or their exact username. There is no directory and no name search for people you do not already talk to — that is deliberate, and it is why strangers cannot find you either.
Name matching exists, but only within conversations you are already part of, which makes it a convenience rather than a discovery tool.
Usernames match exactly. A partial guess returns nothing rather than a list of near misses, which is what stops the feature being used to enumerate accounts.
The other route is a personal link — navenapp.com/add/ followed by a username — which opens a conversation with that person already filled in.