GraphQL is a query language and runtime for APIs that allows clients to request exactly the data they need. Unlike REST, which exposes multiple endpoints, GraphQL provides a single endpoint where clients send structured queries. GraphQL servers define a strongly typed schema describing available data, relationships, and operations. Clients specify fields precisely, reducing over-fetching and under-fetching.
Why it matters
GraphQL improves efficiency for complex applications, particularly frontends that need multiple related data fields. It enables powerful developer tooling, introspection, and predictable API evolution. GraphQL is especially useful for mobile and SPA applications where performance matters.
Examples
A GraphQL query might request a user’s name, email, and recent posts in a single call. Lessons like What Is GraphQL? break down how GraphQL compares to REST.