GraphQL is an opensource Query Language for APIs. It was Created by Facebook in 2012 for use in their Mobile applications. After, it was open sourced in 2015.
“GraphQL is a Query language for your API that shifts the contract between Clients and servers that allows the server to say these are the capabilities that I exposed and allows the clients to describe their requirements in a way that ultimately empower product developers to build the products they want create .” –Dan Schafer, GraphQL Co-Creator.