Hi @ambikaTewari_ATCI
I created a test Recommendations Criteria (HTML Design was disabled), and checked the response from the Delivery API.
It shows me the same output - content type = html
You will need to parse the response escaped string into actual JSON, process to do this will vary depending on the what environment you are calling the API with
Example: In JavaScript I can use replaceAll('\n','') and then JSON.parse() to convert the response content to JSON.