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Applying Rules

Markuplint applies the recommended preset by default when no configuration file is found. Once you have a configuration file, you can customize which rules are active and how they behave.

Customizing preset rules​

If you're using a preset, you can override individual rules without leaving the preset. Presets define named rules in the namespace/rule-name format (e.g., a11y/html-lang), which you can disable, change severity, or bulk-control using a namespace wildcard:

{
  "extends": ["markuplint:recommended"],
  "rules": {
    // Disable a specific named rule
    "a11y/html-lang": false,

    // Change severity of a named rule
    "a11y/no-autofocus-outside-dialog": "warning",

    // Disable all named rules in a namespace
    "a11y/*": false,

    // Disable by base rule name (affects every preset containing it)
    "id-duplication": false
  }
}

When multiple presets wrap the same base rule (e.g., a11y/id-duplication and html-standard/id-duplication), both run independently. Setting the base rule name to false disables it inside every named rule group — see Disabling by base rule name for details.

You can also define your own named rule groups. For the full list of preset named rules, see Named rules in presets.

Enabling individual rules​

Add rules to the rules property in your configuration file. Any value other than false enables the rule:

{
  "rules": {
    "attr-duplication": true,
    "class-naming": "/[a-z]+/",
    "required-attr": {
      "value": "true"
    }
  }
}

Set a rule to false to disable it. See the rules property reference for the full value format.

The complete list of available rules is on the Rules page.

Applying rules to specific elements​

To apply rules only to certain elements, use selectors with the nodeRules or childNodeRules property.

nodeRules applies rules to the matched elements only:

{
  "nodeRules": [
    {
      "selector": "main",
      "rules": {
        "class-naming": "/[a-z]+(__[a-z]+)?/"
      }
    }
  ]
}

childNodeRules applies rules to child elements of the matched elements. Set inheritance to true to include all descendants:

{
  "childNodeRules": [
    {
      "selector": ".legacy-section",
      "inheritance": true,
      "rules": {
        // Also disables virtual rules like a11y/wai-aria
        "wai-aria": false
      }
    }
  ]
}

You can use base rule names (e.g., "wai-aria") and namespace wildcards (e.g., "a11y/*": false) in both nodeRules and childNodeRules. These automatically apply to virtual rules created by presets — see the nodeRules reference for details.

Using custom rules​

You can use rules created by third-party developers or create your own. Specify the plugin name and rule name separated by a slash:

{
  "plugins": ["./my-plugin.js"],
  "rules": {
    "my-plugin/my-rule": true
  }
}

Next steps​