I need to handle social activity events in my web app application developed using Vue JS framework and Firebase.
I want to show to the user “Facebook like” notifications when some activity happen in the application, for example:
“John liked your post”.
Is Firebase Cloud Messaging useful for this scenario? Or do I have to develop some custom solution from scratch?
If Firebase Cloud Messaging do the job, is it possible to send messages directly from user web client?
You should not try to send messages directly from the web client. FCM is intended to be used via a secure backend where your code runs to send messages. The reason a backend is needed is to prevent your private server key from being exposed to the world, which can cause security issues in your app.
You will have to arrange on your backend to determine when events occur that should generate messages, and use the Firebase Admin SDK to send those message, or work with the REST API directly.