GraphQL SDL
GraphQL is a query language and runtime for APIs, defined by the GraphQL Specification. The GraphQL Schema Definition Language (SDL) is the declarative format used to define types, queries, mutations, and subscriptions on a GraphQL server. The spec is governed by the GraphQL Foundation, a Linux Foundation project, under the OWFa 1.0 license. The current spec edition is the October 2021 release with continued Working Drafts.