Heads up! This blog post hasn't been updated in over 2 years. CodePen is an ever changing place, so if this post references features, you're probably better off checking the docs. Get in touch with support if you have further questions.

Slim lovers, we finally have proper syntax highlighting and correct editor behavior for you. This is thanks to CodeMirror 4.5 which had it in it’s release, we just upgraded to it =).

In addition to just the nice, terse syntax, you can do things that HTML can’t, like loops.

To activate Slim, choose it from the HTML Settings:

Emmet doesn’t output in Slim (yet), but you can write regular HTML right within Slim (like Markdown or Jade can as well), so we left it active. We did update our custom tab triggers to output in Slim though, for instance try ul-TAB: