if static data is enough, you can simple place it to files and serve as simple http
you don't even need to run apache or a node.js file server for this.
just put your responses into files on a relative path according to your request. eg: api/product/31.json api/product?orderby=name api/product?orderby=price
so if you have a demo webapp just package the static data with your app and redirect/configure api calls to the service in the live app