Damn,I have so much to learn still. Does this corespond to a NIP or is it just the setup of the permissions on the relay. I guess the only wat to have this kind of inbox is to host your own relay?
Discussion
It correspond to the NIPs 51 and 17. The event of kind 10050 contain the list of private inbox relays of a user.
If you want this kind of inbox, you can use a free relay like wss://auth.nostr1.com/, a paid relay like wss://inbox.nostr.wine/ or host your own relay.
Tnx for the info. Any hint on which relay software supports 51 and 17 out of the box? I would try to self host...
Probably strfry, every big relays use it.