Free · Find code fences with no language

Markdown Code Language Checker

Check fenced code blocks for missing, unusual, or inconsistent language labels.

  • markdown-it 14 parser
  • Private in your browser
  • Raw HTML stays off

Check code languages

Paste Markdown or open a local .md file. Raw HTML stays off in every preview.

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Add Markdown633 / 120,000 characters
Safe local parsermarkdown-it 14.1.0 · raw HTML disabled
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See the resultReady when you are
Your result will appear here

Nothing is uploaded, and links are never opened by the checker.

Three simple steps

How to use it

  1. Paste the technical Markdown.
  2. Review every fenced block label.
  3. Add a common language name when helpful.

Your Markdown stays on this device

markdown-it reads the document inside this browser tab. Bookify does not upload or save it. Raw HTML is shown as text, unsafe link types stay unclickable, and the checker never visits a link.