title: Firebase Cloud Massaging - Push Notifications Server Keys Handle
body: <p>I want to add push notification to my app with Firebase Cloud Messaging but I don't know the right way to set this up.</p>
  <p>My App Logic is: I have multiple customers (companies) who host their own server's own database and their own users. Some of the employees of the different customers will download the app to receive push notifications from their company's server which implements the firebase admin SDK to send push notifications.</p>
  <p>How is it possible to handle all customers from one FCB or is it even possible?</p>
  <p>So the customer can just enter the created „server key/topic or project id / UUID“ to his server configuration and can receive the push notification.<br />
  They should also not be allowed to see any data from other customers or send messages to them.
  At the end of the day, I need to handle all customer</p>