FCM can send message to clients who subscribes to certain topic and it states the below:
Topic messaging supports unlimited topics and subscriptions for each app.
Topic messaging is best suited for content such as news, weather, or other publicly available information.
Topic messages are optimized for throughput rather than latency. For fast, secure delivery to single devices or small groups of devices, target messages to tokens, not topics.
If you need to send messages to multiple devices per user, consider Device Group messaging for those use cases.
Seems to be suitable for our app, but with small number of users, we might not need this with small number of users.
FCM can send message to clients who subscribes to certain topic and it states the below:
Seems to be suitable for our app, but with small number of users, we might not need this with small number of users.