path: root/docs/content/en/getting-started/configuration-markup.md

---
title: Configure markup
description: Configure rendering of markup to HTML.
categories: [getting started,fundamentals]
keywords: [markup,markdown,goldmark,asciidoc,asciidoctor,highlighting]
menu:
  docs:
    parent: getting-started
    weight: 50
weight: 50
slug: configuration-markup
toc: true
---

## Default handler

Hugo uses [Goldmark] to render Markdown to HTML.

{{< code-toggle file=hugo >}}
[markup]
defaultMarkdownHandler = 'goldmark'
{{< /code-toggle >}}

Files with the `.md` or `.markdown` extension are processed as Markdown, provided that you have not specified a different [content format] using the `markup` field in front matter.

To use a different renderer for Markdown files, specify one of `asciidocext`, `org`, `pandoc`, or `rst` in your site configuration.

defaultMarkdownHandler|Description
:--|:--
`asciidocext`|[AsciiDoc]
`goldmark`|[Goldmark]
`org`|[Emacs Org Mode]
`pandoc`|[Pandoc]
`rst`|[reStructuredText]

To use AsciiDoc, Pandoc, or reStructuredText you must install the relevant renderer and update your [security policy].

{{% note %}}
Unless you need a unique capability provided by one of the alternate Markdown handlers, we strongly recommend that you use the default setting. Goldmark is fast, well maintained, conforms to the [CommonMark] specification, and is compatible with [GitHub Flavored Markdown] (GFM).

[commonmark]: https://spec.commonmark.org/0.30/
[github flavored markdown]: https://github.github.com/gfm/
{{% /note %}}

[asciidoc]: https://asciidoc.org/
[content format]: /content-management/formats/#formats
[emacs org mode]: https://orgmode.org/
[goldmark]: https://github.com/yuin/goldmark/
[pandoc]: https://pandoc.org/
[restructuredtext]: https://docutils.sourceforge.io/rst.html
[security policy]: /about/security/#security-policy

## Goldmark

This is the default configuration for the Goldmark Markdown renderer:

{{< code-toggle config=markup.goldmark />}}

### Goldmark extensions

The extensions below, excluding Extras and Passthrough, are enabled by default.

Extension|Documentation|Enabled
:--|:--|:-:
cjk|[Goldmark Extensions: CJK]|:heavy_check_mark:
definitionList|[PHP Markdown Extra: Definition lists]|:heavy_check_mark:
extras|[Hugo Goldmark Extensions: Extras]|
footnote|[PHP Markdown Extra: Footnotes]|:heavy_check_mark:
linkify|[GitHub Flavored Markdown: Autolinks]|:heavy_check_mark:
passthrough|[Hugo Goldmark Extensions: Passthrough]|
strikethrough|[GitHub Flavored Markdown: Strikethrough]|:heavy_check_mark:
table|[GitHub Flavored Markdown: Tables]|:heavy_check_mark:
taskList|[GitHub Flavored Markdown: Task list items]|:heavy_check_mark:
typographer|[Goldmark Extensions: Typographer]|:heavy_check_mark:

[GitHub Flavored Markdown: Autolinks]: https://github.github.com/gfm/#autolinks-extension-
[GitHub Flavored Markdown: Strikethrough]: https://github.github.com/gfm/#strikethrough-extension-
[GitHub Flavored Markdown: Tables]: https://github.github.com/gfm/#tables-extension-
[GitHub Flavored Markdown: Task list items]: https://github.github.com/gfm/#task-list-items-extension-
[Goldmark Extensions: CJK]: https://github.com/yuin/goldmark?tab=readme-ov-file#cjk-extension
[Goldmark Extensions: Typographer]: https://github.com/yuin/goldmark?tab=readme-ov-file#typographer-extension
[Hugo Goldmark Extensions: Extras]: https://github.com/gohugoio/hugo-goldmark-extensions?tab=readme-ov-file#extras-extension
[Hugo Goldmark Extensions: Passthrough]: https://github.com/gohugoio/hugo-goldmark-extensions?tab=readme-ov-file#passthrough-extension
[PHP Markdown Extra: Definition lists]: https://michelf.ca/projects/php-markdown/extra/#def-list
[PHP Markdown Extra: Footnotes]: https://michelf.ca/projects/php-markdown/extra/#footnotes

#### Extras

{{< new-in 0.126.0 >}}

Enable [deleted text], [inserted text], [mark text], [subscript], and [superscript] elements in Markdown.

Element|Markdown|Rendered
:--|:--|:--
Deleted text|`~~foo~~`|`<del>foo</del>`
Inserted text|`++bar++`|`<ins>bar</ins>`
Mark text|`==baz==`|`<mark>baz</mark>`
Subscript|`H~2~O`|`H<sub>2</sub>O`
Superscript|`1^st^`|`1<sup>st</sup>`

[deleted text]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/del
[inserted text]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/ins
[mark text]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/mark
[subscript]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/sub
[superscript]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/sup

To avoid a conflict when enabling the Hugo Goldmark Extras subscript extension, if you want to render subscript and strikethrough text concurrently you must:

1. Disable the Goldmark strikethrough extension
2. Enable the Hugo Goldmark Extras delete extension

For example:

{{< code-toggle file=hugo >}}
[markup.goldmark.extensions]
strikethrough = false

[markup.goldmark.extensions.extras.delete]
enable = true

[markup.goldmark.extensions.extras.subscript]
enable = true
{{< /code-toggle >}}

#### Passthrough

{{< new-in 0.122.0 >}}

Enable the passthrough extension to include mathematical equations and expressions in Markdown using LaTeX or TeX typesetting syntax. See [mathematics in Markdown] for details.

[mathematics in Markdown]: content-management/mathematics/

#### Typographer

The Typographer extension replaces certain character combinations with HTML entities as specified below:

Markdown|Replaced by|Description
:--|:--|:--
`...`|`&hellip;`|horizontal ellipsis
`'`|`&rsquo;`|apostrophe
`--`|`&ndash;`|en dash
`---`|`&mdash;`|em dash
`«`|`&laquo;`|left angle quote
`“`|`&ldquo;`|left double quote
`‘`|`&lsquo;`|left single quote
`»`|`&raquo;`|right angle quote
`”`|`&rdquo;`|right double quote
`’`|`&rsquo;`|right single quote

### Goldmark settings explained

Most of the Goldmark settings above are self-explanatory, but some require explanation.

###### duplicateResourceFiles

{{< new-in 0.123.0 >}}

(`bool`) If `true`, shared page resources on multilingual single-host sites will be duplicated for each language. See [multilingual page resources] for details. Default is `false`.

[multilingual page resources]: /content-management/page-resources/#multilingual

{{% note %}}
With multilingual single-host sites, setting this parameter to `false` will enable Hugo's [embedded link render hook] and [embedded image render hook]. This is the default configuration for multilingual single-host sites.

[embedded image render hook]: /render-hooks/images/#default
[embedded link render hook]: /render-hooks/links/#default
{{% /note %}}

###### parser.wrapStandAloneImageWithinParagraph

(`bool`) If `true`, image elements without adjacent content will be wrapped within a `p` element when rendered. This is the default Markdown behavior. Set to `false` when using an [image render hook] to render standalone images as `figure` elements. Default is `true`.

[image render hook]: /render-hooks/images/

###### parser.autoHeadingIDType

(`string`) The strategy used to automatically generate heading `id` attributes, one of `github`, `github-ascii` or `blackfriday`.

- `github` produces GitHub-compatible `id` attributes
- `github-ascii` drops any non-ASCII characters after accent normalization
- `blackfriday` produces `id` attributes compatible with the Blackfriday Markdown renderer

This is also the strategy used by the [anchorize](/functions/urls/anchorize) template function. Default is `github`.

###### parser.attribute.block

(`bool`) If `true`, enables [Markdown attributes] for block elements. Default is `false`.

[Markdown attributes]: /content-management/markdown-attributes/

###### parser.attribute.title

(`bool`) If `true`, enables [Markdown attributes] for headings. Default is `true`.

###### renderHooks.image.enableDefault

{{< new-in 0.123.0 >}}

(`bool`) If `true`, enables Hugo's [embedded image render hook]. Default is `false`.

[embedded image render hook]: /render-hooks/images/#default

{{% note %}}
The embedded image render hook is automatically enabled for multilingual single-host sites if [duplication of shared page resources] is disabled. This is the default configuration for multilingual single-host sites.

[duplication of shared page resources]: /getting-started/configuration-markup/#duplicateresourcefiles
{{% /note %}}

###### renderHooks.link.enableDefault

{{< new-in 0.123.0 >}}

(`bool`) If `true`, enables Hugo's [embedded link render hook]. Default is `false`.

[embedded link render hook]: /render-hooks/links/#default

{{% note %}}
The embedded link render hook is automatically enabled for multilingual single-host sites if [duplication of shared page resources] is disabled. This is the default configuration for multilingual single-host sites.

[duplication of shared page resources]: /getting-started/configuration-markup/#duplicateresourcefiles
{{% /note %}}

###### renderer.hardWraps

(`bool`) If `true`, Goldmark replaces newline characters within a paragraph with `br` elements. Default is `false`.

###### renderer.unsafe

(`bool`) If `true`, Goldmark renders raw HTML mixed within the Markdown. This is unsafe unless the content is under your control. Default is `false`.

## AsciiDoc

This is the default configuration for the AsciiDoc renderer:

{{< code-toggle config=markup.asciidocExt />}}

### AsciiDoc settings explained

###### attributes

(`map`) A map of key-value pairs, each a document attributes. See Asciidoctor’s [attributes].

[attributes]: https://asciidoctor.org/docs/asciidoc-syntax-quick-reference/#attributes-and-substitutions

###### backend

(`string`) The backend output file format. Default is `html5`.

###### extensions

(`string array`) An array of enabled extensions, one or more of `asciidoctor-html5s`, `asciidoctor-bibtex`, `asciidoctor-diagram`, `asciidoctor-interdoc-reftext`, `asciidoctor-katex`, `asciidoctor-latex`, `asciidoctor-mathematical`, or `asciidoctor-question`.

{{% note %}}
To mitigate security risks, entries in the extension array may not contain forward slashes (`/`), backslashes (`\`), or periods. Due to this restriction, extensions must be in Ruby's `$LOAD_PATH`.
{{% /note %}}

###### failureLevel

(`string`) The minimum logging level that triggers a non-zero exit code (failure). Default is `fatal`.

###### noHeaderOrFooter

(`bool`) If `true`, outputs an embeddable document, which excludes the header, the footer, and everything outside the body of the document. Default is `true`.

###### preserveTOC

(`bool`) If `true`, preserves the table of contents (TOC) rendered by Asciidoctor. By default, to make the TOC compatible with existing themes, Hugo removes the TOC rendered by Asciidoctor. To render the TOC, use the [`TableOfContents`] method on a `Page` object in your templates. Default is `false`.

[`TableOfContents`]: /methods/page/tableofcontents/

###### safeMode

(`string`) The safe mode level, one of `unsafe`, `safe`, `server`, or `secure`. Default is `unsafe`.

###### sectionNumbers

(`bool`) If `true`, numbers each section title. Default is `false`.

###### trace

(`bool`) If `true`, include backtrace information on errors. Default is `false`.

###### verbose

(`bool`)If `true`, verbosely prints processing information and configuration file checks to stderr. Default is `false`.

###### workingFolderCurrent

(`bool`) If `true`, sets the working directory to be the same as that of the AsciiDoc file being processed, allowing [includes] to work with relative paths. Set to `true` to render diagrams with the [asciidoctor-diagram] extension. Default is `false`.

[asciidoctor-diagram]: https://asciidoctor.org/docs/asciidoctor-diagram/
[includes]: https://docs.asciidoctor.org/asciidoc/latest/syntax-quick-reference/#includes

### AsciiDoc configuration example

{{< code-toggle file=hugo >}}
[markup.asciidocExt]
    extensions = ["asciidoctor-html5s", "asciidoctor-diagram"]
    workingFolderCurrent = true
    [markup.asciidocExt.attributes]
        my-base-url = "https://example.com/"
        my-attribute-name = "my value"
{{< /code-toggle >}}

### AsciiDoc syntax highlighting

Follow the steps below to enable syntax highlighting.

Step 1
: Set the `source-highlighter` attribute in your site configuration. For example:

{{< code-toggle file=hugo >}}
[markup.asciidocExt.attributes]
source-highlighter = 'rouge'
{{< /code-toggle >}}

Step 2
: Generate the highlighter CSS. For example:

```text
rougify style monokai.sublime > assets/css/syntax.css
```

Step 3
: In your base template add a link to the CSS file:

{{< code file=layouts/_default/baseof.html >}}
<head>
  ...
  {{ with resources.Get "css/syntax.css" }}
    <link rel="stylesheet" href="{{ .RelPermalink }}" integrity="{{ .Data.Integrity }}" crossorigin="anonymous">
  {{ end }}
  ...
</head>
{{< /code >}}

Then add the code to be highlighted to your markup:

```text
[#hello,ruby]
----
require 'sinatra'

get '/hi' do
  "Hello World!"
end
----
```

### AsciiDoc troubleshooting

Run `hugo --logLevel debug` to examine Hugo's call to the Asciidoctor executable:

```txt
INFO 2019/12/22 09:08:48 Rendering book-as-pdf.adoc with C:\Ruby26-x64\bin\asciidoctor.bat using asciidoc args [--no-header-footer -r asciidoctor-html5s -b html5s -r asciidoctor-diagram --base-dir D:\prototypes\hugo_asciidoc_ddd\docs -a outdir=D:\prototypes\hugo_asciidoc_ddd\build -] ...
```

## Highlight

This is the default `highlight` configuration. Note that some of these settings can be set per code block, see [Syntax Highlighting](/content-management/syntax-highlighting/).

{{< code-toggle config=markup.highlight />}}

For `style`, see these galleries:

* [Short snippets](https://xyproto.github.io/splash/docs/all.html)
* [Long snippets](https://xyproto.github.io/splash/docs/longer/all.html)

For CSS, see [Generate Syntax Highlighter CSS](/content-management/syntax-highlighting/#generate-syntax-highlighter-css).

## Table of contents

This is the default configuration for the table of contents, applicable to Goldmark and Asciidoctor:

{{< code-toggle config=markup.tableOfContents />}}

###### startLevel

(`int`) Heading levels less than this value will be excluded from the table of contents. For example, to exclude `h1` elements from the table of contents, set this value to `2`. Default is `2`.

###### endLevel

(`int`) Heading levels greater than this value will be excluded from the table of contents. For example, to exclude `h4`, `h5`, and `h6` elements from the table of contents, set this value to `3`. Default is `3`.

###### ordered

(`bool`) If `true`, generates an ordered list instead of an unordered list. Default is `false`.