First, can you clarify if you are implementing App Broker for ServiceNow integration, where ServiceNow's service catalog or service portal is being used as the front end and App Broker is only serving in a back end capacity; or are you just looking to use App Portal's front end UI and simply integrate with ServiceNow for the purpose of creating tickets on deployment failure or other similar use cases?
In any event, integration from App Portal/Broker to any external system using either the web service framework or the ITSM integration framework is limited to SOAP-based web services. We do not have a REST-based web service/ITSM framework. If you are implementing full App Broker for ServiceNow integration, you'll notice in our documentation that outbound calls from App Broker to ServiceNow are done via SOAP, while inbound calls from ServiceNow to App Broker are done via REST. You can also see in the permissions that are required to integrate with ServiceNow that it requires SOAP permissions. If you absolutely must use REST to communicate with ServiceNow (or any other external system), then you would either have to create your own SOAP wrapper around the REST API's and configure that SOAP wrapper in the ITSM framework, or you could choose to do this using Command Script actions instead of the ITSM framework. We would typically use PowerShell scripts within the Command Script framework for such a REST integration.
Anything expressed here is my own view and not necessarily that of my employer, Flexera. If my reply answers a question you have raised, please click "ACCEPT AS SOLUTION".
