What is response type in Web API?

Web API converts request data into CLR object and also serialize CLR object into response data based on Accept and Content-Type headers. Web API includes built-in support for JSON, XML, BSON, and form-urlencoded data. It means it automatically converts request/response data into these formats OOB (out-of the box).

For More Information Please Refer: https://www.tutorialsteacher.com/webapi/request-response-data-formats-in-web-api