PUSH Notifications

 

https://developer.apple.com/videos/play/wwdc2020/10095/

https://www.youtube.com/watch?v=UJree24HWx0

https://onesignal.com/

https://www.pubnub.com

https://aws.amazon.com/blogs/messaging-and-targeting/getting-started-with-push-notifications-using-aws-amplify/