Creating a new subgraph

This article helps you get started building a new subgraph that you can then add to your GraphOS supergraph.

• If you're building a new GraphQL API from scratch, we recommend
  starting from a template
  !
• If you already have a GraphQL API to use as a subgraph, see
  Starting with an existing API
  .

Starting from a template

The fastest way to create a new subgraph is to start with one of the templates provided by the

You start by running rover template use, providing it the ID of your chosen template. For example, the following command creates a new directory called my-subgraph that contains the boilerplate code for a subgraph written in TypeScript using the Apollo Server library:

rover template use "my-subgraph" --template="subgraph-typescript-apollo-server"

After generating the boilerplate code, you can start filling in your business logic. The generated code includes example resolvers for Query and Mutation, along with some

When you're ready to add your new subgraph to your supergraph,

Starting with an existing API

If you have an existing GraphQL API that you want to use as a subgraph, confirm whether it uses a

• If it does, consult the library's documentation to determine how to enable its support for Apollo Federation.
• If it doesn't,
  open an issue to let us know
  and we'll work with the library's maintainers to add support.

Adding to your supergraph

When you're ready to add a new subgraph to your existing GraphOS supergraph, do the following:

1. Enable federation support in your subgraph library.
   • If you
     built from a template
     , federation support is already enabled. Otherwise, consult the documentation for your chosen library.
2. Check your schema
   against your existing supergraph and handle any conflicts.
3. Set up your CI/CD pipeline to perform checks and also
   publish your subgraph schema
   .

After you publish your subgraph's schema for the first time, GraphOS recognizes it as part of your supergraph, and you can start querying for data from all your subgraphs!