We are happy to announce that Markoff, a lightweight Markdown previewer for OS X, is now available for free on the Mac App Store.

We write a lot of Markdown at thoughtbot. Between README’s, blog posts, and the myriad of online services that support the format in their text fields, there is a high probability that I am writing Markdown when I am not coding or designing.

I don’t know about you, but I prefer using my own editor whenever possible. I spent hours tweaking my colors, plugins, and commands, and I don’t want to give that up for a standalone Markdown editor, regardless of how fancy it might be. The downside of this, however, is that you need to setup your own previewing workflow.

There are both free and paid Markdown previewers on OS X, but alas, issues like slow rendering, feature bloat, and lack of code highlighting and YAML frontmatter support stood in the way and made my experience less enjoyable.

Markoff is an attempt to provide a bare minimum Markdown previewing workflow that is fast, reliable, and hassle-free. Features include:

Uses cmark , a C implementation of CommonMark, for parsing and rendering. This is a lot faster than other existing Ruby and JavaScript solutions.

, a C implementation of CommonMark, for parsing and rendering. This is a lot faster than other existing Ruby and JavaScript solutions. Allows you to select your default editor and open the previewed document in it by hitting Cmd+e , using the menu item, or clicking the toolbar button.

, using the menu item, or clicking the toolbar button. Uses highlight.js for syntax highlighting.

Detects YAML frontmatter and renders it as a special code block.

Auto-reloads the preview whenever the original file is saved. Depending on your editor, you might be able to set up auto-save to get an always up-to-date preview without manually saving.

Shows basic information such as word and character count.

Markoff is open source and can be downloaded directly from the App Store. So, how about you give it a try and let us know what you think?