Markdown Here is a Google Chrome, Firefox, Safari, Opera, and Thunderbird extension that lets you write email† in Markdown‡ and render them before sending. It also supports syntax highlighting (just specify the language in a fenced code block). Writing email with code in it is pretty tedious. Writing Markdown with code in it is easy. I found myself writing email in Markdown in the Github in-browser editor, then copying the preview into email. This is a pretty absurd workflow, so I decided create a tool to write and render Markdown right in the email. To discover what can be done with Markdown in Markdown Here, check out the Markdown Here Cheatsheet and the other wiki pages. Source: https://github.com/adam-p/markdown-here.git.