I’d like my app to be able to send a message to another specific user of the app. Previously I used a text message, but Google has now prohibited apps from doing that, and apparently iOS never allowed it.
The Push Notification doesn’t apply. The idea is that the user of the app wants to notify another user of the app that an event has occurred, and the notification should arrive in real time.
I should add that the existing text message function, which requires manual completion, isn’t very practical for the use case under consideration.
OneSignal push notifications to specific users
Well I think the PUSH Notification from One signal is ur best bet,after which you have signed up u just have to work around the features available in there to filter or sort what you want to achieve
In addition to the PAID option of push notifications, IF the user has the app open, you can use a firebase realtime db listenener. Add an Alert block inside the listener data change block. It will cause the alert to appear regardless of the screen the user is in.
But if they do not have the app open, the One Signal Push notification is the only other solution I know of (Sending Notification to Specific User with Onesignal)