# Apollo Federation

> Federation 2.x subgraph schemas (@key, @shareable)

**Subcategory:** Apollo GraphQL  
**License:** MIT  
**Source:** https://github.com/apollographql/skills/blob/main/skills/apollo-federation/SKILL.md

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## When it is useful

Federation 2.x subgraph schemas (@key, @shareable, composition).

## The Catch

Schema authoring, not the Router runtime.