How to Retrieve the Authentication Type Used for an Existing Instance

The authentication type used on an already authenticated instance can be verified by the platform API call GET/instances/{id}. This API call displays the configuration parameter in which authentication.type  displays the correct authentication type used for the authenticated instance.

Here is an example of a Quickbooks Online authenticated instance:

"configuration": {
 "base.url": "",
 "": null,
 "": "9130346788056166",
 "event.notification.basic.username": "",
 "": "9130346788056166",
 "authentication.type": "oauth2",
 "event.vendor.type": "polling",
 "use_sandbox": "false",
 "filter.response.nulls": "true",
 "pagination.type": "offset",