GraphQL SDL
GraphQL Schema Definition Language (SDL) is a syntax for defining GraphQL schemas in a human-readable format, specifying types, fields, queries, mutations, and subscriptions. It serves as the contract between client and server in a GraphQL API, enabling tools to generate code, validate queries, and provide documentation. SDL is integral to GraphQL's type system, allowing developers to describe data structures and operations declaratively.
Developers should learn GraphQL SDL when building or consuming GraphQL APIs, as it provides a clear, standardized way to define schemas that ensure type safety and facilitate collaboration. It is essential for use cases like API documentation generation, client-side query validation, and server-side implementation in frameworks like Apollo Server or GraphQL.js, helping prevent errors and improve development efficiency.