GraphQL is a query language for APIs, developed by Facebook in 2012 and released as an open-source project in 2015. It allows clients to request exactly the data they need, reducing over-fetching and under-fetching issues common with traditional REST APIs. GraphQL APIs are structured around a single endpoint and use a strong type system to define the data schema, enabling more efficient and flexible data retrieval. This approach empowers developers to build more responsive applications by allowing them to tailor requests to their specific needs.