Core Development Concepts > Extending and Customizing
Extend GraphQL API
Learn how to use GraphQL plugins in order to expand your GraphQL API.
- how to use the
CmsGraphQLSchemaPlugin
in order to extend an existing Headless CMS GraphQL API - how to use the [
GraphQLSchemaPlugin
] in order to extend an existing default GraphQL API
Use the webiny watch
command to continuously deploy application code changes into the cloud and instantly see them in action. For quick (manual) testing, you can use the built-in API Playground.
Introduction
When it comes to HTTP API development, Webiny relies on GraphQL. In fact, all of the applications that are part of the Webiny Serverless CMS, for example Page Builder or Headless CMS, are using it to enable developers programmatic interaction via a client of their choice, for example, a browser.
Extending GraphQL API
In general, when talking about extending an existing GraphQL API, we’re usually referring to one or more of the following:
- adding new query or mutation GraphQL operations
- adding new GraphQL types
- extending existing GraphQL types with additional fields
For example, we might want to add a new, Page Builder-related, duplicatePage
mutation, that would be responsible for making copies of provided pages. Or, we might just want to add an extra field to the PbPage
GraphQL type, so that we can store some additional data for each page.
Depending on the application and the change we want to perform, some of the steps in the overall GraphQL extension process may differ, in all cases, we will want to start by registering a new [GraphQLSchemaPlugin
] plugin.
The plugin is registered within your GraphQL API’s application code [apps/api/graphql/src/plugins
] folder, and register it in the [apps/api/graphql/src/index.ts
] entrypoint file.
The following is an example of a simple CmsGraphQLSchemaPlugin
plugin that extends the default GraphQL API with a new listBooks
query.
Once your plugin is ready, add it to the entrypoint like so:
Declaring your API using GraphQLSchemaPlugin
means your API will be registered under the default API, so your new query (listBooks
) will be visible in the API playground under the Main API tab.
Executing the query should give us the following result:
To extend your default GraphQL API in no time, make sure to try the Extend Admin Area and Extend GraphQL API scaffolds.
In case you wish to extend the Headless CMS API, you would just replace GraphQLSchemaPlugin
with CMSGraphQLSchemaPlugin
in your plugin, and everything else remains the same. Doing this your plugin will be visible under the “Headless CMS - Manage API” tab in the API Playground and you need to use the matching GraphQL URL.
The CmsGraphQLSchemaPlugin
plugin is part of the @webiny/api-headless-cms
package, which can also be used to create new standalone GraphQL APIs.
Additional Related Examples
For more concrete examples, you can also visit the following guides which explain how to extend GraphQL types and operations that belong to different Webiny applications: