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Setting up social cards

Social cards, also known as social previews, are images that are displayed when a link to your project documentation is shared on social media. Material for MkDocs can generate beautiful social cards automatically, using the colors, fonts and logo1 defined in mkdocs.yml, e.g.:

Social cards preview

The social preview image for the page on setting up site analytics. Twitter's Card validator shows how it will look when shared.

Configuration

Built-in social cards

Insiders · insiders-2.12.0 · Plugin · Experimental

First, ensure you've installed all dependencies and have a valid site_url, as social preview images must be referenced via absolute URLs. Then, add the following lines to mkdocs.yml:

plugins:
  - social

The following configuration options are available:

cards

Default: true – This option specifies whether to generate social card images. If you want to switch the plugin off, e.g. for local builds, you can use an environment variable:

plugins:
  - social:
      cards: !ENV [SOCIAL_CARDS, false]
cards_color

insiders-2.13.0 · Default: primary color – This option specifies which colors to use for the background fill and foreground text when generating the social card:

plugins:
  - social:
      cards_color:
        fill: "#0FF1CE" # (1)
        text: "#FFFFFF"
  1. Colors can either be defined as HEX colors, or as CSS color keywords. Note that HEX colors must be enclosed in quotes.
cards_directory

Default: assets/images/social – This option specifies where the generated social card images will be written to. It's normally not necessary to change this option:

plugins:
  - social:
      cards_directory: assets/images/social

Dependencies

Two Python packages are installed alongside Material for MkDocs to generate the social preview images, both of which are based on the Cairo Graphics library:

  • Pillow – Python imaging library
  • CairoSVG – Converter for *.svg files

The Docker image for Insiders comes with all dependencies pre-installed. If you don't want to use Docker, see the following section which explains how to install all dependencies on your system:

Make sure Homebrew is installed, which is a modern package manager for macOS. Next, use the following command to install all necessary dependencies:

brew install cairo freetype libffi libjpeg libpng zlib

As stated in the installation guide, the easiest way to get up and running with the Cairo Graphics library on Windows is by installing GTK+, since it has Cairo as a dependency.

There are several package managers for Linux with varying availability per distribution. The installation guide explains how to install the Cairo Graphics library for your distribution:

apt-get install libcairo2-dev libfreetype6-dev libffi-dev libjpeg-dev libpng-dev libz-dev
yum install cairo-devel freetype-devel libffi-devel libjpeg-devel libpng-devel zlib-devel
zypper install cairo-devel freetype-devel libffi-devel libjpeg-devel libpng-devel zlib-devel

Caching recommended

The built-in social cards plugin automatically fetches the fonts you define in mkdocs.yml from Google Fonts, and uses them to render the text that is displayed on the social card. The font files and generated cards are both written to the .cache directory, which is used in subsequent builds to detect whether the social cards need to be regenerated. You might want to:

  1. Ignore the .cache directory in your project, by adding it to .gitignore.
  2. When building your site for publishing, use a build cache to save the .cache directory in between builds. Taking the example from the publishing guide, add the following lines:

    name: ci
      on:
        push:
          branches:
            - master
            - main
      jobs:
        deploy:
          runs-on: ubuntu-latest
          steps:
            - uses: actions/checkout@v2
            - uses: actions/setup-python@v2
              with:
                python-version: 3.x
            - uses: actions/cache@v2
              with:
                key: ${{ github.ref }}
                path: .cache
            - run: pip install mkdocs-material
            - run: mkdocs gh-deploy --force
    

Meta tags

The built-in social cards plugin automatically sets all necessary meta tags, equivalent to the following two customizations, which you can set manually when you don't want to use it:

{% block extrahead %}
  {% set title = config.site_name %}
  {% if page and page.meta and page.meta.title %}
    {% set title = title ~ " - " ~ page.meta.title %}
  {% elif page and page.title and not page.is_homepage %}
    {% set title = title ~ " - " ~ page.title %}
  {% endif %}
  <meta property="og:type" content="website" />
  <meta property="og:title" content="{{ title }}" />
  <meta property="og:description" content="{{ config.site_description }}" />
  <meta property="og:url" content="{{ page.canonical_url }}" />
  <meta property="og:image" content="<url>" />
  <meta property="og:image:type" content="image/png" />
  <meta property="og:image:width" content="1200" />
  <meta property="og:image:height" content="630" />
{% endblock %}
{% block extrahead %}
  {% set title = config.site_name %}
  {% if page and page.meta and page.meta.title %}
    {% set title = title ~ " - " ~ page.meta.title %}
  {% elif page and page.title and not page.is_homepage %}
    {% set title = title ~ " - " ~ page.title %}
  {% endif %}
  <meta name="twitter:card" content="summary_large_image" />
  <meta name="twitter:title" content="{{ title }}" />
  <meta name="twitter:description" content="{{ config.site_description }}" />
  <meta name="twitter:image" content="<url>" />
{% endblock %}

Usage

If you want to adjust the title or set a custom description for the social card, you can use the Metadata extension, which takes precedence over the default values.


  1. Both types of logos, images (theme.logo) and icons (theme.icon.logo) are supported. While an image logo is used as-is, icons are filled with the color used in the header (white or black), which depends on the primary color. 

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