APNS (Apple Push Notification Service) reliability

37
votes

Our app uses APNS to receive Push Notifications. However, our client claims that some of their devices were not receiving notifications and argues to they 'must' make sure the notifications to be delivered 100%. But I have read somewhere that APNS is not 100% reliable and there should be cases which the notifications are not delivered.

I'm currently panic at how we could make sure APNS to received anytime. I have read that a case which may APNS not delivered (device may offline). But our test showing that even the device is online (Wifi or 3G), sometimes APNS were not delivered.

Is there any specific case which may APNS will not delivered? Or is there anything we (developers) can do with codes to make sure to receive all notifications? What I have done in the code is just registering the app to remote notification and write didRegisterForRemoteNotificationsWithDeviceToken, then throw the device token to our server.

Any help would be appreciated, for our client almost kill us if ALL of their devices not receiving APNS!

4
iospush-notificationapple-push-notifications
Yeah, it's not reliable, in the normal network sense of the word. – Nate
Is the backend pushing the messages to APNS controlled by you as well? In that case you should be able to log if some sendings to APNS fails and you could look and see if the feedback-service contains the tokens for the devices not getting the messages. – johan
Thank you for quick reply johan! If you are talking about the server-side, yes they're controlled by our PHP server. According to one of our developers who's in charge of server-side development, currently looks like the APNS messages were sended successfully. And the device sometimes gets notification, sometimes not. I'm getting confused and crazy about this APNS things... – Faust V
@Nate Aw, that's shame... In a sense, maybe you're right. But our client's so called 'iOS guru' said "there's NO case that APNS could fail with sending messages!" Maybe he's just an "Apple fanboy" or something? – Faust V
I don't know if he's an Apple fanboy or not, but he's wrong on this issue, technically. It says it right in the documentation. Search for "best effort". – Nate

4 Answers

45
votes
  1. APNS is based on Apple Servers, and Apple doesn't give any guarantee on successful message delivery.
  2. If the app is open (i.e. the user is using the app) while the notification arrives, iOS doesn't show a notification message, you need to handle it.
  3. Notification shows up only when the app is backgrounded or killed.
  4. Also implement feedback service on your server side; will help you get rid of old unwanted tokens (users who deleted the app or disabled notifications through settings).
  5. Don't send too many notifications to a device within a short span of time, because APNS caches only 1 message/device (if the device is offline). So it can deliver the message when the device comes online. Am not sure how long the message is cached though.

Or just implement Pusher... http://pusher.com

8
votes

We're facing the same problem. As everybody said, APNS is a best effort service so you can't be sure every notification will be delivered, but what you can do is to be sure of which ones have been received. This is what we're about to do. We register in our backend each notification que ship and the mobile app reports back each notification it receives. Then we set a maximum time of waiting for a notification to be received, if we don't receive the report back we try again.

I hope it might be helpful to someone (even 2 years later)

4
votes

It says it quite clearly in the Apple Docs that it is not 100% gauranteed and nor should it be used as so. Its sent with "best effort".

0
votes

As per Apple's guidelines, APNS is not 100% reliable service that means your app may not get the push notifications from Apple servers due to some of following reasons:

  • Device is offline
  • Your app is in the foreground state, you need to manage the push notification.

Note: Apple rejects app which makes compulsion using notification services. (I have faced it in one of my App)

For more information, you can look into this answer

https://stackoverflow.com/a/25830955/3278326