What is the Relay specification in GraphQL?

The Relay specification is a set of conventions developed by Facebook/Meta for structuring GraphQL APIs to work optimally with the Relay client (but adopted broadly). Key conventions: (1) Global Object Identification: every object has a globally unique id: ID! field, and the root query has a node(id: ID!): Node field to fetch any object by ID. (2) Cursor Connections: a standardized pagination pattern using Connection, Edge, and PageInfo types. (3) Mutation conventions: mutations accept a single input argument and return a payload object. Following the Relay spec makes APIs more consistent, enables powerful client-side caching, and allows Relay's automatic store normalization. Even when not using Relay client, following these conventions makes your API more standardized and tooling-friendly.