I ran across Understanding And Using REST APIs — Smashing Magazine, which is an entry level article explaining REST APIs and uses the GitHub API v3 in its examples.
By default, all requests to https://api.github.com receive the v3 version of the REST API. We encourage you to explicitly request this version via the Accept header.
GitHub chose GraphQL for our API v4 because it offers significantly more flexibility for our integrators. The ability to define precisely the data you want—and only the data you want—is a powerful advantage over the REST API v3 endpoints. GraphQL lets you replace multiple REST requests with a single call to fetch the data you specify.
Back in April 2015, I was curious about Facebook GraphQL/Relay and Netflix Falcor and knew it was a technology to watch. Is now the time not to assume that API doesn’t always equal REST?