Firebase Notification - send to user segment vs send to topic difference

Question

I am assigned a task to use Firebase to implement push notifications but I am kind of new this.

Looking at the documentation:

https://firebase.google.com/docs/notifications/android/console-audience

I can't tell under what circumstances should I use send to user segment or send to a topic.

Can someone please give me some example when to use one or the other and point out the difference? Thanks ahead :)

Answer 1

User Segments

• You can only send notifications to User Segments via the Firebase Console. (see here).
• Limited to specific targets (from the docs you linked):

  Select the message target. The dialog displays further options to refine the target based on whether you choose App/App Version, Device Language, or Users in Audience.

• As also already mentioned in the doc you linked:

  You can target predefined user segments or custom audiences created in Firebase Analytics.

Topics

• Token/device management not necessarily required.
• Unlimited number of subscribers.
• Can send to topics using the FCM API.
• Can easily subscribe/unsubscribe via the client app.

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_{IMHO, if you want things to be quick and simple, go with Topic Messaging.}

Answer 2

Use User segements

• To typically send push notifications to a specific and limited set of devices.
• Message delivery is almost instantaneous (in my experience). Also, I haven't observed throttling as was the case earlier with GCM.

Use Topics

• Topic or publish/subscribe mechanism is used for a comparatively larger audience and the information type is public. Examples are weather and news.
• Topics have latency (Message delivery may be throttled)