Markdown

Astro comes with out-of-the-box Markdown support powered by the expansive remark ecosystem.

Parsers

Astro lets you use any Markdown parser you want. It just needs to be a function that follows the MarkdownParser type declared inside this file. You can declare it inside astro.config.mjs:

// astro.config.mjs
export default {
  markdownOptions: {
    render: [
      'parser-name', // or import('parser-name') or (contents) => {...}
      {
        // options
      },
    ],
  },
};

Astro comes with the @astrojs/markdown-remark package - the default parser.

Remark and Rehype Plugins

In addition to custom components inside the <Markdown> component, the default parser comes with these plugins pre-enabled:

Also, Astro supports third-party plugins for Markdown. You can provide your plugins in astro.config.mjs.

Note: Enabling custom remarkPlugins or rehypePlugins removes Astro’s built-in support for the plugins previously mentioned. You must explicitly add these plugins to your astro.config.mjs file, if desired.

Add a Markdown plugin in Astro

If you want to add a plugin, you need to install the npm package dependency in your project and then update remarkPlugins or rehypePlugins inside the @astrojs/markdown-remark options depending on what plugin you want to have:

// astro.config.mjs
export default {
  markdownOptions: {
    render: [
      '@astrojs/markdown-remark',
      {
        remarkPlugins: [
          // Add a Remark plugin that you want to enable for your project.
          // If you need to provide options for the plugin, you can use an array and put the options as the second item.
          // ['remark-autolink-headings', { behavior: 'prepend'}],
        ],
        rehypePlugins: [
          // Add a Rehype plugin that you want to enable for your project.
          // If you need to provide options for the plugin, you can use an array and put the options as the second item.
          // 'rehype-slug',
          // ['rehype-autolink-headings', { behavior: 'prepend'}],
        ],
      },
    ],
  },
};

You can provide names of the plugins as well as import them:

// astro.config.mjs
export default {
  markdownOptions: {
    render: [
      '@astrojs/markdown-remark',
      {
        remarkPlugins: [
          [import('remark-autolink-headings'), { behavior: 'prepend' }],
        ],
      },
    ],
  },
};

Markdown Pages

Astro treats any .md files inside of the /src/pages directory as pages. These files can contain frontmatter, but are otherwise processed as plain markdown files and do not support components. If you’re looking to embed rich components in your markdown, take a look at the Markdown Component section.

Layouts

Markdown pages have a special frontmatter property for layout. This defines the relative path to an .astro component which should wrap your Markdown content, for example a Layout component. All other frontmatter properties defined in your .md page will be exposed to the component as properties of the content prop. The rendered Markdown content is placed into the default <slot /> element.

---
# src/pages/index.md
layout: ../../layouts/BaseLayout.astro
title: My cool page
---

# Hello World!
---
// src/layouts/BaseLayout.astro
const { content } = Astro.props;
---
<html>
  <head>
    <title>{content.title}</title>
  </head>

  <body>
    <slot />
  </body>
</html>

For Markdown files, the content prop also has an astro property which holds special metadata about the page such as the complete Markdown source and a headers object. An example of what a blog post content object might look like is as follows:

{
  /** Frontmatter from a blog post
  "title": "Astro 0.18 Release",
  "date": "Tuesday, July 27 2021",
  "author": "Matthew Phillips",
  "description": "Astro 0.18 is our biggest release since Astro launch.",
  **/
  "astro": {
    "headers": [
      {
        "depth": 1,
        "text": "Astro 0.18 Release",
        "slug": "astro-018-release"
      },
      {
        "depth": 2,
        "text": "Responsive partial hydration",
        "slug": "responsive-partial-hydration"
      }
      /* ... */
    ],
    "source": "# Astro 0.18 Release\\nA little over a month ago, the first public beta [...]"
  },
  "url": ""
}

Keep in mind that the only guaranteed properties coming from the content prop are astro and url.

Images and videos

Using images or videos follows Astro’s normal import rules:

  • Place them in the public/ as explained on the project-structure page
    • Example: Image is located at /public/assets/img/astonaut.png → Markdown: ![Astronaut](assets/img/astronaut.png)
  • Or use import as explained on the imports page (when using Astro’s Markdown Component)

Astro’s Markdown Component

Astro has a dedicated component used to let you render your markdown as HTML components. This is a special component that is only exposed to .astro files. To use the <Markdown> component, within your frontmatter block use the following import statement:

---
import { Markdown } from 'astro/components';
---

You can utilize this within your .astro file by doing the following:

---
import { Markdown } from 'astro/components';
---

<Layout>
  <Markdown>
    # Hello world!

    The contents inside here is all in markdown.
  </Markdown>
</Layout>

<Markdown> components provide more flexibility and allow you to use plain HTML or custom components. For example:

---
// For now, this import _must_ be named "Markdown" and _must not_ be wrapped with a custom component
// We're working on easing these restrictions!
import { Markdown } from 'astro/components';
import Layout from '../layouts/main.astro';
import MyFancyCodePreview from '../components/MyFancyCodePreview.tsx';

const expressions = 'Lorem ipsum';
---

<Layout>
  <Markdown>
    # Hello world!

    **Everything** supported in a `.md` file is also supported here!

    There is _zero_ runtime overhead.

    In addition, Astro supports:
    - Astro {expressions}
    - Automatic indentation normalization
    - Automatic escaping of expressions inside code blocks

    ```js
      // This content is not transformed!
      const object = { someOtherValue };
    ```

    - Rich component support like any `.astro` file!
    - Recursive Markdown support (Component children are also processed as Markdown)

    <MyFancyCodePreview client:visible>
      ```js
      const object = { someOtherValue };
      ```
    </MyFancyCodePreview client:visible>
  </Markdown>
</Layout>

Remote Markdown

If you have Markdown in a remote source, you may pass it directly to the Markdown component through the content attribute. For example, the example below fetches the README from Snowpack’s GitHub repository and renders it as HTML.

---
import { Markdown } from 'astro/components';

const content = await fetch('https://raw.githubusercontent.com/snowpackjs/snowpack/main/README.md').then(res => res.text());
---

<Layout>
  <Markdown content={content} />
</Layout>

There might be times when you want to combine both dynamic, and static markdown. If that is the case, you can nest <Markdown> components with each other to get the best of both worlds.

---
import { Markdown } from 'astro/components';

const content = await fetch('https://raw.githubusercontent.com/snowpackjs/snowpack/main/README.md').then(res => res.text());
---

<Layout>
  <Markdown>
    ## Markdown example

    Here we have some __Markdown__ code. We can also dynamically render content from remote places.

    <Markdown content={content} />
  </Markdown>
</Layout>

Security FAQs

Aren’t there security concerns to rendering remote markdown directly to HTML?

Yes! Just like with regular HTML, improper use of the Markdown component can open you up to a cross-site scripting (XSS) attack. If you are rendering untrusted content, be sure to sanitize your content before rendering it.

Why not use a prop like React’s dangerouslySetInnerHTML={{ __html: content }}?

Rendering a string of HTML (or Markdown) is an extremely common use case when rendering a static site and you probably don’t need the extra hoops to jump through. Rendering untrusted content is always dangerous! Be sure to sanitize your content before rendering it.