Apple Push Notification reliablity

Question

The topic I want to discuss may be a duplicate of this question. But still I've a few queries regarding Apple Push Notifications.

I have one app supported on both Android and iOS. The app needs a background service which hits a remote server every minute. The job is simple for Android app but since background tasking is not supported in iOS I need to employ push notifications for iOS app. I am using PushSharp library to deliver push notifications. Apple says that the delivery of push notification is not acknowledged. I cannot afford push notification failure since I need to send a very crucial message through notification. My questions are:

1) What is the failure rate of push notifications?

2) Are push notifications always reliable to send important messages?

3) Assume that the server which is supposed to send push notifications sends a large number of push notifications every minute. What are the chances of push notification failure in such a case?

4) Which circumstances cause push notification delivery to fail?

If you have any useful resources please provide the same. Thanks.

Answer 1

Please find my comments below.Hope this helps.

1. What is the failure rate of push notifications?
   • Apple has not disclosed it so far.
2. Are push notifications always reliable to send important messages?
   • Delivery of notifications is a “best effort”, not guaranteed. It is not intended to deliver data to your app, only to notify the user that there is new data available.
   • Please refer - https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html
3. Assume that the server which is supposed to send push notifications sends a large number of push notifications every minute. What are the chances of push notification failure in such a case?
   • Only one recent notification for a particular application is stored. If multiple notifications are sent while the device is offline, each new notification causes the prior notification to be discarded. This behavior of keeping only the newest notification is referred to as coalescing notifications.
   • Please refer - https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html
4. Which circumstances cause push notification delivery to fail?
   • If APNs attempts to deliver a notification but the device is offline, the notification is stored for a limited period of time, and delivered to the device when it becomes available.
   • Please refer - https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html