GraphQL is an open-source query language and runtime for APIs (Application Programming Interfaces) that Facebook developed. It provides a more efficient and flexible approach to fetching and manipulating data compared to traditional RESTful APIs. GraphQL allows clients to request only the specific data they need, making it more efficient in terms of network usage and reducing over-fetching or under-fetching of data.
GraphQL was initially developed by Facebook in 2012 to address the challenges they faced with their mobile applications. They needed a more efficient way to retrieve data from their servers, as the traditional RESTful APIs led to over-fetching of data and multiple roundtrips to the server. Facebook introduced GraphQL internally in 2012 and later released it publicly in 2015.