Heading Structure Analyzer

What this tool checks

This tool extracts every heading from a page — either HTML <h1> through <h6> tags, or Markdown # through ###### lines — and rebuilds them into a nested tree so you can see the outline at a glance. It then runs three structural checks: whether there's exactly one H1, whether any heading level is skipped (jumping from H2 straight to H4, for example), and whether any headings exist at all.

These aren't cosmetic checks. Search engines and screen readers both use heading structure to understand a page's outline; a broken hierarchy makes content harder to parse for both audiences, independent of how well-written the prose is.

When to use it

Use it before publishing any page where headings matter for SEO — blog posts, documentation, landing pages — especially ones assembled from multiple sections or written by different contributors, where heading levels tend to drift. It's also useful when auditing an existing site: paste the rendered HTML (view-source or a saved DOM snapshot) to check whether a CMS template is accidentally emitting two H1s, which is a common WordPress and page-builder bug.

For Markdown-based static sites (Docusaurus, Hugo, Jekyll, MDX), paste the raw source directly — the tool detects Markdown headings automatically when no HTML tags are present, so you can check heading structure before the content ever gets built.

Example

Paste `# Getting Started\n### Installation\n## Configuration` and the tool flags "Skipped heading level: H1 → H3 (at \"Installation\")" — because the content jumped from H1 to H3 without an H2 in between, even though it later has an H2. Fixing it means changing "### Installation" to "## Installation" so each level increases by exactly one step.