Raw HTML disappears from markdown without saying anything

Sun, 20 Sep 2026 16:24:00 -0500

Put an iframe in a markdown file and it renders as nothing. Not a broken element, not a comment, not a warning in the build log. The element simply isn’t in the HTML, as though I’d never typed it.

Goldmark — Hugo’s markdown renderer — discards raw HTML unless you tell it otherwise:

[markup.goldmark.renderer]
  unsafe = true

I’ll defend the name. It’s site-wide and it re-enables all raw HTML in all markdown, which is a sensible thing to refuse when content might come from someone else, and a sensible thing to allow on a personal site where I wrote every file.

goldmark on jwogrady

Raw HTML disappears from markdown without saying anything