GraphQL is a query language and server-side runtime for APIs, developed by Facebook in 2012 and open-sourced in 2015. It allows clients to request exactly the data they need, making APIs more efficient and flexible compared to traditional REST APIs.
GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.