Apollo Federation

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 @apollo/utils.withrequired @as-integrations/h3 graphql

2. Configure Subgraph

// nitro.config.ts
export default defineNitroConfig({
  modules: ['nitro-graphql'],
  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
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
export default defineNitroConfig({
  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
export default defineNitroConfig({
  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