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Is there a way for server application that sends topic messages over FCM to find out which topics actually have subscribers?

We have potentially large number of topics and would like to avoid having to always push messages to all of them since only a subset would be active at any given time. I know that server can query about particular InstanceID's subscribed topics, but iterating over thousands of them sounds like a bad idea.

We can roll our own solution, but since that information already exists in Firebase itself, it would be preferred to just get it from there.

jpop
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  • I see. No worries. Will delete my answer so that the community would see this as no answer yet. Cheers! – AL. Jul 13 '16 at 10:36

1 Answers1

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No. There is no current way to query the number of subscribers to a topic, you would have to maintain the relationship between token and topics on you app server.

Arthur Thompson
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  • Thanks, that seems to be the only option at the moment. – jpop Jul 16 '16 at 09:07
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    Sad but true. What I do is- I use topics for my notifications, but I also keep saving the user with its token in my Firebase db. Or else how will you ever know when more than a 1000 subscriptions per product are being made? – user3833732 Jul 14 '17 at 09:40