Citrine is a nostr relay that you run on an android phone.

When Citrine first came out, @isolabellart posted about it here (#460134). I don't think there is much development happening on it.

I was recently listening to Gigi interviewing Arjen on the Sovereign Engineering podcast and they were both talking about using Citrine as a way to get rid of the feeling of being offline.

The way they descried it is that you would run a (private?) Citrine on your phone and then all your other nostr apps would post notes to it first. In turn, your instance of Citrine would be connected to other relays. If you are offline, it simply builds up a que of notes to broadcast when you are next online again.

I have a feeling there is more to it than this, but the dynamic they described is that of making it feel like you are never offline. If you lose connectivity or are in airplane mode, you might not load new notes from others, but you would keep using your nostr apps as normal with Citrine acting as a nostr relay to which you are always connected (because it is local).

This concept of running things local is something they've been focusing on a lot lately. It's cool to see in a world where it feels like AI is pulling everything off our machines.