Markdown Formatter & Cleaner

Use the formatter when a Markdown document has accumulated inconsistent syntax from different editors, contributors, pasted sources, or AI tools. One pass can standardize heading syntax, bullet markers, ordered-list numbering, emphasis markers, blank lines, trailing spaces, and the final newline. Protected content is restored exactly after formatting, so fenced code, inline code, YAML frontmatter, and HTML blocks keep their original content.

The GitHub README preset is tuned for README and documentation Markdown: it renumbers ordered lists from 1, formats and aligns tables, keeps task list checkboxes (- [ ] / - [x]) intact, and preserves YAML frontmatter used by static site generators and GitHub Pages. Fenced code blocks showing install commands or usage examples are protected throughout, so they render exactly as written after formatting.

Markdown generated by ChatGPT, Claude, Gemini, and similar tools often mixes heading styles, alternates between - and * bullets, restarts numbered lists at 1 repeatedly, and leaves excessive blank lines between sections. The AI Cleanup preset normalizes all of this in one pass — renumbering ordered lists, standardizing bullet markers and emphasis style, and adding consistent spacing around headings — without changing the actual wording of the content.

Table formatting remains available as a supporting document-cleanup rule. It rebuilds separator rows, pads columns, and preserves left, center, and right alignment markers. Malformed tables are left unchanged with a warning instead of being guessed at. For creating tables from CSV or spreadsheet data, editing cells visually, validating GFM, or repairing a table-focused workflow, use the dedicated Markdown Table Generator.