Add an authorized app of the Backend Service type and save it. For example: myapp_send (Send from my app).
This authorized app represents the client side of the application, that is calling ION through API Gateway.
Download credentials. In the Download Credentials window, select Create Service Account. You do not have to specify a user name. This is not required because ION does not authorize incoming requests based on user authorizations.
You require the authorized app credential file when you configure the application.