How to listen events from another application

I am looking for some ideas and references to any docs if anyhow a frappe app can listen to events from another cloud application. Need a hint for listening events and not webhook/API. Please guide on this.

You can write custom api method to listen other app’s webhook

check this if it helps Sample app to publish and subscribe to MQTT5

Thank you @revant_one, it should fulfil the objective and we will explore and understand it.