BDD when testing a web service / API
BDD when testing a web service / API
I think you can do what your writing about in BDD. Im not sure if those 2 links about testing of webservices with SpecFlow will help you but take a look on them if you havent seen it yet.
http://codedetective.blogspot.co.uk/2012/10/testing-webservices-with-specflow.html
http://www.creamdog.se/blog/2011/02/24/webservices-automated-tests-using-specflow-and-babelfish/
Have a look at Karate, web service testing framework by Intuit. Its recently being open sourced. It has the capability of handling API dealing with HTML, JSON, XML, GraphQL queries and is built on top on cucumber.
Simple intro here : https://medium.com/blueprint-by-intuit/karate-web-services-testing-made-simple-366e8eb5adc0#.qnpy5gagt