npm install --save-dev markdownlint markdownlint-cli
# or
pnpm add -D markdownlint markdownlint-cli
# or
yarn add -D markdownlint markdownlint-cli

npx markdownlint --version

{
  "default": true,
  "MD003": { "style": "atx_closed" },
  "MD007": { "indent": 4 },
  "no-hard-tabs": false,
  "whitespace": false
}

{
  "MD001": false,
  "heading-increment": false,
  "MD003": { "style": "atx" },
  "heading-style": { "style": "atx" },
  "no-inline-html": {
    "allowed_elements": ["strong", "em", "br"]
  }
}

{
  "default": true
}

{
  "default": false,
  "MD001": true,
  "MD003": { "style": "atx" },
  "line-length": true
}

{
  "heading-style": {
    "style": "atx"
  }
}

{
  "ul-style": {
    "style": "asterisk"
  }
}

{
  "ul-indent": {
    "indent": 4,
    "start_indented": true
  }
}

{
  "line-length": {
    "line_length": 100,
    "heading_line_length": 120,
    "code_block_line_length": 120,
    "code_blocks": true,
    "tables": false,
    "headings": true,
    "strict": false,
    "stern": false
  }
}

{
  "no-trailing-spaces": {
    "br_spaces": 2,
    "list_item_empty_lines": false,
    "strict": false
  }
}

{
  "no-inline-html": {
    "allowed_elements": [
      "strong",
      "em",
      "br",
      "sub",
      "sup",
      "kbd",
      "details",
      "summary"
    ]
  }
}

{
  "hr-style": {
    "style": "---"
  }
}

{
  "first-line-heading": {
    "level": 1,
    "front_matter_title": ""
  }
}

{
  "required-headings": {
    "headings": [
      "# Title",
      "## Description",
      "## Examples",
      "## Resources"
    ]
  }
}

{
  "proper-names": {
    "names": [
      "JavaScript",
      "TypeScript",
      "GitHub",
      "markdownlint",
      "npm"
    ],
    "code_blocks": false
  }
}

<!-- markdownlint-disable-file -->

# This file has no linting applied

Any markdown content here will not be checked.

<!-- markdownlint-disable-file MD013 MD033 -->

# Long lines and HTML are allowed in this file

This line can be as long as you want without triggering MD013.

<div>Inline HTML is also allowed</div>

<!-- markdownlint-disable MD033 -->

<div class="custom-block">
  HTML content here
</div>

<!-- markdownlint-enable MD033 -->

Regular markdown content with rules enforced.

This line follows all rules.

Long line that exceeds limit <!-- markdownlint-disable-line MD013 -->

This line follows all rules again.

<!-- markdownlint-disable-next-line MD013 -->
This is a very long line that would normally trigger the line-length rule but won't because of the comment above.

This line follows normal rules.

<!-- markdownlint-capture -->
<!-- markdownlint-disable -->

Any violations allowed here.

<!-- markdownlint-restore -->

Back to original configuration.

<!-- markdownlint-configure-file {
  "line-length": {
    "line_length": 120
  },
  "no-inline-html": {
    "allowed_elements": ["strong", "em"]
  }
} -->

# Document Title

Rest of document follows inline configuration.

{
  "$schema": "https://raw.githubusercontent.com/DavidAnson/markdownlint/main/schema/markdownlint-config-schema.json",
  "default": true,
  "MD003": { "style": "atx" },
  "MD007": { "indent": 2 },
  "MD013": {
    "line_length": 100,
    "code_blocks": false
  },
  "MD033": {
    "allowed_elements": ["br", "strong", "em"]
  }
}

default: true
MD003:
  style: atx
MD007:
  indent: 2
MD013:
  line_length: 100
  code_blocks: false
MD033:
  allowed_elements:
    - br
    - strong
    - em

module.exports = {
  default: true,
  MD003: { style: "atx" },
  MD007: { indent: 2 },
  MD013: {
    line_length: 100,
    code_blocks: false
  },
  MD033: {
    allowed_elements: ["br", "strong", "em"]
  }
};

{
  "default": true,
  "line-length": {
    "line_length": 100
  }
}

{
  "extends": "base.json",
  "no-inline-html": false,
  "line-length": {
    "line_length": 120
  }
}

{
  "extends": "markdownlint/style/relaxed"
}

{
  "$schema": "https://raw.githubusercontent.com/DavidAnson/markdownlint/main/schema/markdownlint-config-schema.json",
  "default": true
}

project/
├── .markdownlint.json          # Root config
├── docs/
│   ├── .markdownlint.json      # Docs-specific config
│   └── guides/
│       └── .markdownlint.json  # Guides-specific config

{
  "default": true,
  "line-length": {
    "line_length": 100
  }
}

{
  "extends": "../../../.markdownlint.json",
  "no-inline-html": {
    "allowed_elements": ["code", "pre", "div"]
  }
}

{
  "default": true,
  "heading-style": { "style": "atx" },
  "ul-style": { "style": "dash" },
  "ol-prefix": { "style": "ordered" },
  "line-length": {
    "line_length": 80,
    "strict": true
  },
  "no-trailing-spaces": {
    "strict": true
  },
  "no-inline-html": false,
  "first-line-heading": {
    "level": 1
  },
  "required-headings": {
    "headings": [
      "# Title",
      "## Description",
      "## Usage",
      "## API"
    ]
  }
}

{
  "default": true,
  "line-length": false,
  "no-inline-html": {
    "allowed_elements": [
      "img",
      "a",
      "strong",
      "em",
      "br",
      "div",
      "span"
    ]
  },
  "no-duplicate-heading": {
    "siblings_only": true
  },
  "first-line-heading": false,
  "single-title": false
}

{
  "default": true,
  "line-length": {
    "line_length": 120,
    "code_blocks": false,
    "tables": false
  },
  "no-inline-html": {
    "allowed_elements": [
      "details",
      "summary",
      "kbd",
      "sub",
      "sup",
      "br"
    ]
  },
  "code-block-style": {
    "style": "fenced"
  },
  "code-fence-style": {
    "style": "backtick"
  },
  "emphasis-style": {
    "style": "asterisk"
  },
  "strong-style": {
    "style": "asterisk"
  }
}

{
  "default": true,
  "line-length": {
    "line_length": 100,
    "tables": false,
    "code_blocks": false
  },
  "no-inline-html": {
    "allowed_elements": [
      "img",
      "br",
      "details",
      "summary",
      "sup"
    ]
  },
  "required-headings": {
    "headings": [
      "# *",
      "## Installation",
      "## Usage",
      "## License"
    ]
  },
  "first-line-heading": {
    "level": 1
  }
}