Markdown Linter
Check your Markdown for style and formatting errors instantly. Real-time lint results with rule IDs, line numbers, and clickable navigation. Browser-based, no data sent to server.
How to Use
- Paste or type Markdown in the left pane.
- Lint results appear in real time on the right — no button press needed.
- Click any result to jump to that line in the editor.
- Fix the flagged issues and watch the results update instantly.
What Gets Checked
The linter applies the full set of markdownlint rules, including:
- MD001 — Heading levels should only increment by one level at a time
- MD009 — No trailing spaces at end of lines
- MD010 — No hard tabs (use spaces instead)
- MD012 — No multiple consecutive blank lines
- MD022 — Headings should be surrounded by blank lines
- MD025 — Only one top-level heading per document
- MD031 — Fenced code blocks surrounded by blank lines
- MD034 — No bare URLs — use link syntax instead
- MD041 — First line should be a top-level heading
Privacy
All processing is client-side. Your Markdown content is never uploaded or stored.
Related Tools
- Markdown Preview — Render your Markdown as HTML with live preview
- Markdown Table Generator — Build well-formatted tables visually
FAQ
Is my content sent to a server?
No. All linting happens entirely in your browser using JavaScript. Your Markdown never leaves your machine.
Which rules does the linter check?
The linter runs all standard markdownlint rules — over 50 checks covering heading levels, trailing spaces, blank lines, bare URLs, list style, code fence formatting, and more.
What does a rule ID like MD001 mean?
Rule IDs follow the markdownlint convention: MD001 means 'heading-increment', MD009 means 'no-trailing-spaces', MD041 means 'first-line-heading', and so on. Each result links to the full rule documentation.
Can I click on a result to jump to that line?
Yes. Clicking any lint result scrolls the editor to the offending line and selects it so you can fix it immediately.
How does this differ from the CLI markdownlint tool?
The CLI tool integrates with your build pipeline and can check files on disk. This browser tool is for quick checks while writing or reviewing Markdown without installing anything.