Sending 10000+ push notifications but not all devices receive it

3
votes

For our iOS news apps we send out more than 10000 push notifications to registered devices, but somehow not all devices seem to receive the notification. We have been doing this for years but recently we received user feedback stating they did not receive a push notification while they did register their device to receive them.

Our logs show that these specific devices registered successfully and that there were no errors sending the push notification, but somehow the APNS does not deliver the notification. We have seen that removing the app from the device and reinstalling it sometimes solves the problem but we are still concerned.

We think it must be Apple's service that fails to deliver the push notification sometimes, especially when it comes to sending large amounts of notifications. Any of you experienced this?

The Apple docs says this:

Important: Delivery of notifications is a “best effort”, not guaranteed.

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Recently during testing an application, we were not able to send the notifications if the device list exceeds 2 lacs. – Puneet Sharma
@Puneet 2 lacs? You mean devices? That's somewhat small. Or 2 lakh as in 200,000? – nanofarad
Yes 2lacs as in 200000. I dnt know whether there is an issue in my understanding of Push notification or some Apple issue. – Puneet Sharma
Apple says there is no limit imposed (yet). Bus as docs say, it's best effort. What's the percentage of users saying they didn't receive notifications? Also note that some will be user error. – Marcus Adams
Does the app send the device token to your servers every time the app starts (it should)? Do you store multiple tokens for each user since they might have multiple devices (you should)? Are you sending multiple push notifications to each device at once? (the APNS service will only queue 1 payload for each device if it can't be reached) – Mike Weller

1 Answers

0
votes

Have you checked the payload size? As per Apple's documentation, the maximum size allowed for a notification payload is 256 bytes.