Heading Structure Analyzer
Extract H1-H6 from HTML, view the heading outline as a tree, count per-level, and detect SEO issues: multiple H1s, missing H1, skipped levels, long headings, and empty headings. Export as markdown. 100% client-side.
About Heading Structure Analyzer
Extract H1-H6 from HTML, view the heading outline as a tree, count per-level, and detect SEO issues: multiple H1s, missing H1, skipped levels, long headings, and empty headings. Export as markdown. 100% client-side. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
Why does heading structure matter for SEO?
Search engines use headings to understand the topic and structure of a page. A clear H1 → H2 → H3 hierarchy helps crawlers and screen readers navigate. Common issues: multiple H1s (confusing), missing H1 (no clear topic), skipped levels (H2 → H4 breaks the outline), and headings over 60 characters (may be truncated).
How does the analyzer extract headings?
We use a regex to match <h1>…<h6> tags (case-insensitive, with attributes). The inner HTML is stripped of nested tags and decoded for entities, so the visible text is what we analyze.
What issues does it detect?
Five: (1) multiple H1 tags — best practice is one; (2) missing H1 — every page needs one; (3) skipped levels — e.g., H2 → H4 (don't skip for styling); (4) long headings over 60 chars; (5) empty headings with no text.
What extra features does this tool have compared to others?
(1) Heading tree visualization (H2 nests under H1). (2) Per-level count (H1-H6). (3) Word count per heading. (4) Five SEO issue detectors. (5) Markdown outline export. (6) Numbered outline export (1, 1.1, 1.2 form). (7) Copy outline to clipboard. (8) Long-heading (>60 chars) flagging. (9) History (localStorage, last 20). (10) Shareable URL — encode HTML in the fragment.
Can I fetch a URL to analyze?
Not directly — most websites block cross-origin fetches from the browser. Use your browser's View Source or DevTools, copy the HTML, and paste it here. This keeps the tool 100% client-side and offline-capable.
Is my data sent anywhere?
No. Heading extraction runs locally with regex. History is stored in localStorage on this device only.
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