This is basically a copy of @Block Open Source Buzz's Projects design, but it's fully E2E encrypted and not tied to a single relay. So you can do this on existing Nostr infra without self-hosting any server!

This is the way. Nukes a couple of my pain points with Buzz so far.

Very cool

This is really cool, congrats! 👏👏👏 But so far, Concord needs special relays, right? Or would it work fine with any existing relay? I wrote this note the other day but never got a response. Maybe you can clear my doubts View quoted note →

You are correct in that it requires an open relay with no nip17/DM/spam/expiry protections in place.

Also the deletion issue, in a normal relay anyone could delete anything because everyone share the same stream key, therefore deletion requests are valid. Maybe not important in a "trusted" environment, but critical flag in a public o big group

Not really. It helps to have a relay that prevents giftwrap deletion by the sender, but it's not strictly required. Without it the worst that can happen is that any member can delete all messages from the relay, which might be considered a feature to some rather than a bug. Devices sync and keep the events offline and wouldn't be impacted by such deletions. But we do use relays that prevent giftwrap deletion by the sender (the recipient can still delete them), and this solves that issue. So tl;dr not strictly required but good to have.

Also, Concord communities in practice have a handful of relays (about 5 or 6), not just the 2. The 2 in the app are for things like profile lookups, but once you're actually in a community the community uses its own relay list.

This is very interesting yes, deletion of a whole group from anyone, including invisible members.. I'm looking at the specs again to glean what I can about what it all means, and what it specifically would mean for relay operators / push notification providers, infra standpoint.