Before starting my article, It would be better to mention that I am not going to discuss about how to implement and set up the Firebase push notifications here. I am going to discuss only push notification testing using Postman.
First, follow the below steps to set up Postman to send Firebase notifications.
(to find server key Go to your firebase console and select your Firebase Project, Click on Settings icon >Project Settings > Cloud Messaging > Server Key )
After following these steps, you can send push notifications and find out whether the Firebase push notifications are working for you or not.