7.9 Use a custom HTML template (*)

We mentioned LaTeX templates in Section 6.10. You can also specify a custom HTML template for Pandoc to convert Markdown to HTML. Below is a brief example template:

    <link rel="stylesheet" href="$css$" type="text/css" />

You can see that the template contains a few variables such as $title$ and $body$. You can find the full list of Pandoc variables and their meanings at https://pandoc.org/MANUAL.html#templates.

The template gives you the ultimate power to customize the HTML output. For example, you can include arbitrary CSS stylesheets or JavaScript code or libraries in the <head> area. For example, we could use a Boolean variable draft to indicate whether the document is a draft or a final version:

<style type="text/css">
.logo {
  float: right;

<div class="logo">
<!-- use draft.png to show that this is a draft -->
<img src="images/draft.png" alt="Draft mode" />
<!-- insert the formal logo if this is final -->
<img src="images/logo.png" alt="Final version" />


Then we can set the variable draft to true or false in the YAML metadata of the Rmd document, e.g.,

title: "An Important Report"
draft: true

To apply a template to an Rmd document, you can save the template to a file, and pass the file path to the template option of html_document, e.g.,

    template: my-template.html

The rmarkdown package uses a custom HTML template shipped with the package, which is different from Pandoc’s default template. To use the latter, you can specify template: null.