Question

One thing I haven’t found is when to call the Apple’s Feedback Service for push notifications. The Local and Push Notification Programming Guide says:

Providers should periodically query the feedback service to get the list of device tokens for their applications, each of which is identified by its topic. Then, after verifying that the application hasn’t recently been re-registered on the identified devices, a provider should stop sending notifications to these devices.

But is there a best practice to follow? E.g.:

1. Everyone calls it before sending any notification, or
2. Everyone calls it once a day, or
3. Everyone calls it once a week, or
4. …

Answer 1

You can call the feedback service every day, or if you send lots of notifications in a day, every hour if it’s not a problem for you.

The reason to call the feedback service is to reduce the number of subscribers to include in the next send.

The frequency of calling depends of the frequency of the sending of notifications.