Devs can a Webhook be implemented in Android.? What I want is to observe a URL on which the back end might send multiple POSTs for a while...
I suggested them that we can use Push Notifications instead of Webhook but the back end devs won't listen...

Receiver of a webhook have to have a HTTP server. You can listen HTTP in Android, but it might be a bad idea if you send the webhook from external network, since networking would be a nightmare and there's too much downtime.

I'd suggest receiving a webhook in a proper server and from there syncing it to Android or just emailing it.

@joas Syncing it to Android meaning, should I poll the server for any new data...?

@StanTheMan or relay it through some socket or just pusher it.. :)