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Add a Subgraph

Add a subgraph to your supergraph using a template or existing API

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

Before you get started, you may want to check out the Graphs and Variants article for a conceptual overview.

Starting from a template

The fastest way to create a new subgraph is to start with one of the templates provided by the Rover CLI . The rover template command generates the skeleton of a new subgraph for you, so you can immediately begin defining your schema and implementing your resolvers.

💡 tip
If your installed version of Rover doesn't include the template command (or if you don't have Rover installed at all), install the latest version.

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:

Bash
rover template use "my-subgraph" --template="subgraph-typescript-apollo-server"
💡 tip
To see the full list of available templates, see the Rover template docs

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 entity types to use as your starting point. All templates also come with example GitHub Actions workflows to help with publishing your schema in CI/CD .

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

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 subgraph-compatible library .

  • 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

You can add your new subgraph to your GraphOS supergraph in the following ways:

Adding a subgraph in GraphOS Studio

ⓘ note
This method of adding a subgraph is available only to cloud supergraphs. For other graph types, see Adding a subgraph via the Rover CLI

  1. Go to your variant's Subgraphs page in Studio.

  2. Click Add a subgraph.

  3. In the dialog that appears, provide your subgraph's Routing URL (this is the URL that your supergraph's router will use to communicate with the subgraph), along with a Subgraph Name.

  4. If Studio can't fetch your subgraph's schema automatically from the routing URL, click Advanced options to provide the schema another way (such as by pasting the schema directly or introspecting a locally running server).

  5. Click Add Subgraph. When the action completes, your new subgraph is listed on the Subgraphs page.

Adding a subgraph via the Rover CLI

To add a subgraph to your supergraph with Rover, you publish the subgraph's schema! To do this, you use the exact same Rover command as updating an existing subgraph . The only difference is that you provide the name of the new subgraph to the command.

Learn about publishing subgraph schemas.

Next steps

Make sure you configure your router so that only GraphOS can query it.