Explanation
Adding Stock Responses as an API Gateway Back End:
You'll often want to verify that an API has been successfully deployed on an API gateway without having to set up an actual back-end service. One approach is to define a route in the API deployment specification that has a path to a 'dummy' back end. On receiving a request to that path, the API gateway itself acts as the back end and returns a stock response you've specified.
Equally, there are some situations in a production deployment where you'll want a particular path for a route to consistently return the same stock response without sending a request to a back end. For example, when you want a call to a path to always return a specific HTTP status code in the response.
Using the API Gateway service, you can define a path to a stock response back end that always returns the same:
HTTP status code
HTTP header fields (name-value pairs)
content in the body of the response
"type": "STOCK_RESPONSE_BACKEND" indicates that the API gateway itself will act as the back end and return the stock response you define (the status code, the header fields and the body content).
References:
https://docs.cloud.oracle.com/en-us/iaas/Content/APIGateway/Tasks/apigatewayaddingstockresponses.htm