Create an API which uses postman client and gets data from e commerce solution -- 2

We need to create an API which uses postman client and gets data from our e commerce solution, [login to view URL] All our products are stored in their back end and to access it, we need to create API in XML format. The api should respond using postman ([login to view URL]) from our website solution. We should be able to export some fields and import them using POSTMAN. We need to export using this: [login to view URL]