Apollo Federation

Category

Build distributed GraphQL architectures with Apollo Federation support.

What is Federation?

Apollo Federation allows you to split your GraphQL API across multiple services (subgraphs) that are composed into a single supergraph.

Setup

1. Install Dependencies

pnpm add @apollo/server @apollo/subgraph graphql graphql-config nitro-graphql@beta

2. Configure Subgraph

// nitro.config.ts
import graphql from 'nitro-graphql'
import { defineNitroConfig } from 'nitro/config'

export default defineNitroConfig({
  modules: [
    graphql({
      framework: 'apollo-server',
      federation: {
        enabled: true,
        serviceName: 'users-service',
      },
    }),
  ],
})

3. Define Schema with Federation

# server/graphql/schema.graphql
type User @key(fields: "id") {
  id: ID!
  name: String!
  email: String!
}

extend type Post @key(fields: "id") {
  id: ID! @external
  author: User!
}

4. Implement Reference Resolvers

// server/graphql/users.resolver.ts
import { defineResolver } from 'nitro-graphql/define'

export const userResolver = defineResolver({
  User: {
    __resolveReference: (reference) => {
      return findUser(reference.id)
    },
  },
  Post: {
    author: post => findUser(post.authorId),
  },
})

Example: Multi-Service Setup

Users Service

// users-service/nitro.config.ts
import graphql from 'nitro-graphql'
import { defineNitroConfig } from 'nitro/config'

export default defineNitroConfig({
  modules: [
    graphql({
      framework: 'apollo-server',
      federation: {
        enabled: true,
        serviceName: 'users',
      },
    }),
  ],
})

type User @key(fields: "id") {
  id: ID!
  name: String!
  email: String!
}

Posts Service

// posts-service/nitro.config.ts
import graphql from 'nitro-graphql'
import { defineNitroConfig } from 'nitro/config'

export default defineNitroConfig({
  modules: [
    graphql({
      framework: 'apollo-server',
      federation: {
        enabled: true,
        serviceName: 'posts',
      },
    }),
  ],
})

extend type User @key(fields: "id") {
  id: ID! @external
  posts: [Post!]!
}

type Post @key(fields: "id") {
  id: ID!
  title: String!
  content: String!
  authorId: ID!
}

Gateway Setup

Use Apollo Gateway or Apollo Router to compose subgraphs.

Next Steps

• Apollo Server Guide
• Framework Comparison
• Playground Example

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Source

Contributors

productdevbook alexanderop

Changelog

26362refactor: rename defineType to defineField across documentation and examples

0.2.0 on