GraphQL is both an open source query language for an API and a server-side runtime for executing queries. It enables the use of a type system that developers define for their data.
GraphQL supports reading, writing, and subscribing to changes to data, and SDKs and servers are available for multiple languages, including JavaScript, Python, Ruby, Java, C#, Go, Rust, PHP, and more.
GraphQL is rapidly becoming a popular alternative to REST and gRPC, particularly for exposing data at the edge of systems.