From what I've gathered, the idea behind GraphQL (and GraphiQL the visualisation tool) is the next paradigm in convenience for handling APIs after the standard of RESTful ones, though it is 'backward compatible' -- the idea being you can send a highly selective queries and receive back a highly structured/hierarchical JSON response. I mean I've just barely practised using either of the two methods, but it seems like the way to go for API design ;)