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Schema Linting

Enforce GraphQL formatting conventions and best practices

provides schema linting to help you enforce formatting conventions and other best practices with every proposed change to your graph's schema.

Linter violations in GraphOS Studio
  • If you set up schema checks for your , linting runs as a separate check type alongside build and checks.
  • You can also perform one-off linting with the Rover CLI.


GraphOS schema linting only analyzes parts of your modified schema that differ from your published schema. It does not flag any existing violations.

Linter configuration

The GraphOS schema linter uses a predefined collection of rules to identify issues with proposed schema changes. The predefined collection includes schema composition rules. The graph-wide linter defaults you define apply to all of a particular graph.

To navigate to your linter configuration:

  1. In GraphOS Studio, go to your graph's Checks page.
  2. Click Configuration in the upper right to open the checks configuration page.
  3. From the checks configuration page, open the Linter section.

This page organizes linter options into the following categories:

  • General Linter Configuration provides high-level options, including disabling the linter entirely.
  • Approved @tag names enables you to specify approved values for the name of the @tag . This directive is used most commonly with GraphOS contracts.
    • If you don't use the @tag directive, you can ignore this category.
    • Using a non-approved value for name raises the TAG_DIRECTIVE_USES_UNKNOWN_NAME violation.
  • Rule Severity Configuration enables you to set the severity level for violations of each rule.

If you view this configuration for a single , each category displays a Use Graph Settings toggle in the upper right. If this toggle is enabled, the variant uses whatever graph-wide defaults are set for that category. At this time, the Use Graph Settings toggle is always enabled for all variants.

Setting severity levels

The Rules Severity Configuration category of your linter configuration displays all predefined rules and the current severity level for each. Click a rule's severity to set it to any of the following:

  • Error: Any violation of this rule causes the associated linter check to fail.
    • This in turn causes the entire run to fail, which is useful for failing builds in CI.
  • Warn: Violations of this rule are flagged in checks reports, but they don't cause the associated linter check to fail.
  • Ignore: Violations of this rule are ignored entirely.

For information on specific rules, see the reference list of rules.

Running the linter

Schema linting runs automatically as part of your graph's schema checks. You can also perform one-off linting of local schema changes via the .

Linting via schema checks

If you set up schema checks for your graph, schema linting automatically runs as a separate check type alongside build and operation checks. You can view the results of all check types from your graph's Checks page in Studio. For example, the screenshot below shows successful build and checks with a failed linting check.

Checks page in Studio showing all check types


For the best experience running linter checks, install v0.16 or later of the Rover CLI. Earlier versions of Rover can't correctly output the results of linter checks, but they do correctly exit with a nonzero code if a linter check fails.

One-off linting


One-off linting requires v0.16 or later of the Rover CLI. Install the latest version.

The Rover CLI provides subgraph lint and graph lint commands for running the GraphOS linter against your local schema changes.

  • Use subgraph lint for in a .
  • Use graph lint for monographs (not recommended).

The rover subgraph lint and rover graph lint commands validate all linter rules except for composition rules. Use rover subgraph check or rover supergraph compose to validate rules locally.

Example command
rover subgraph lint --name products --schema ./products-schema.graphql my-graph@my-variant

The argument my-graph@my-variant in the example above is a that specifies the ID of the graph you're comparing your schema changes against, along with which variant you're comparing against.

Command options include:


Required. The path to a local .graphql or .gql file, in SDL format.

Alternatively, you can provide -, in which case the command uses an string piped to stdin instead (see Using stdin).


Required for subgraph lint. Omit for graph lint. The name of the published to compare schema changes against.


If provided, the linter only flags violations that are present in the diff between your local schema and your published schema.

By default, one-off linting flags all violations in your local schema.

Linter rules

See this reference list of rules.

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