Is it possible to make RESTful Calls from Grafana to my API's (HTTP GET) for example

I am new to Grafana and I am interested in learning more how or if I am able to access JSON payloads via RESTful calls to URL’s or URI’s to Web services or File Resources.

If you want to embed content from a web service in a Grafana dashboard then I would recommend this plugin:

Or do you mean something else?