# known-types

Source: https://apigenie.pl/docs/linter/graphql/rules/known-types

This rule checks that the types referenced by type system definitions are built-in scalars or defined in the document, as the GraphQL specification requires.

## Rule Details

The rule reports the issues of the validation rule of the same name, with the messages of graphql-js. A document that breaks it is rejected by GraphQL servers and tools, so the rule should stay enabled with the `error` severity.

## Configuration

This rule has no options.

```yaml
version: "1.0"
commands:
  lint:
    graphql:
      rules:
        known-types: warning
```

The rule can be disabled for a node and everything nested in it with an `# apigenie-lint-disable known-types` comment on the node, or for a whole file with the comment at the top of the file, separated from the first definition by a blank line. It applies to definitions.

## Examples

**Good**.

```graphql
type Query { user: User }
type User { id: ID! }
```

**Bad**. The linter reports `Unknown type "User".`.

```graphql
type Query { user: User }
```

## Compatibility

The rule reports references to types and fragments that are not in the document only when the configuration sets `self_contained: true`, since schemas and operations are often split across files.