Introduction
The GraphQL Composite Schemas Spec introduces a comprehensive specification for creating distributed GraphQL systems that seamlessly merges multiple GraphQL schemas. This specification describes the process of composing a federated GraphQL schema and outlines algorithms for executing GraphQL queries on the federated schema effectively by using query plans. This specification was originally created by ChilliCream and was transferred to the GraphQL foundation.
The GraphQL Foundation was formed in 2019 as a neutral focal point for organizations who support the GraphQL ecosystem, and the GraphQL Specification Project was established also in 2019 as the Joint Development Foundation Projects, LLC, GraphQL Series.
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The GraphQL Specification Project has evolved and may continue to evolve in future editions of this specification. Previous editions of the GraphQL specification can be found at permalinks that match their release tag. The latest working draft release can be found at https://spec.graphql.org/draft.
Copyright notice
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Conformance
A conforming implementation of the GraphQL Composite Schemas Spec must fulfill all normative requirements. Conformance requirements are described in this document via both descriptive assertions and key words with clearly defined meanings.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in the normative portions of this document are to be interpreted as described in IETF RFC 2119. These key words may appear in lowercase and still retain their meaning unless explicitly declared as non-normative.
A conforming implementation of the GraphQL Composite Schemas Spec may provide additional functionality, but must not where explicitly disallowed or would otherwise result in non-conformance.
Non-Normative Portions
All contents of this document are normative except portions explicitly declared as non-normative.
Examples in this document are non-normative, and are presented to aid understanding of introduced concepts and the behavior of normative portions of the specification. Examples are either introduced explicitly in prose (e.g. "for example") or are set apart in example or counter-example blocks, like this:
This is an example of a non-normative example.
This is an example of a non-normative counter-example.
Notes in this document are non-normative, and are presented to clarify intent, draw attention to potential edge-cases and pit-falls, and answer common questions that arise during implementation. Notes are either introduced explicitly in prose (e.g. "Note: ") or are set apart in a note block, like this:
Note: This is an example of a non-normative note.