I have used some API testing tools like PostMan, fiddler, and SoapUI etc. I have used these to test API mostly written in ASP. Net WEB API. I have a requirement to create an application which will be used to invoke API request and receive other API request. I thought about it and i think why i create an application to invoke API request if i already have API testing tool but need to create an application to receive API request and return edited responses. I know we can capture the API request, but is there any way to edit the API request response in any API testing tool?
It sounds like a job for soapUI mocking. You can define the response to a call as either a fixed message; a random sequence of canned responses; based on an XPath or XQuery expression; or you can write your own Groovy script to fully customise the response. I've used mocks to test complex interactions and to test parts of my requests and response.