1. Is the endpoint call from the Rest client a POST method?
2. Is the endpoint an HTTPS call? Is it an HTTP call?
3. Is there a Java SDK supplied from the Rest client? If there is provision, I would like a manual and sample of how to use it.
If not provided, I would like to know the endpoint API specification (header, request parameters, response result, HTTP status code etc).
1. "Route via HTTP Assertion" requests PUSH notification to the FCM endpoint by HTTP, so it is the POST method.
2. The API GW endpoint can be either HTTPS or HTTP.
3. Especially SDK is not prepared.
To the end point to API GW, it is only to transmit with "Route via HTTP Assertion".