Problem:

Background data limits on iOS and aggressive background task killing on Android prevent Nostr clients from generating private and group chat notifications. Centralized apps, like Snapchat and Slack, get around this by utilizing the iOS/Android push notification services.

Solution:

Nostr client apps could register their npub with a service, paid with a few sats, capable of generating iOS and Android push notifications. The service would watch for private and group chat message types destined for that npub and generate a push message to the client telling it to wake up and retrieve the messages from the relays. The client's nsec key is never exposed, and the push service can be untrusted.