Heading Structure Checker (H1–H6)

Paste HTML to validate H1–H6 hierarchy, detect skips, and generate a clean heading outline.

Heading Structure Checker (H1–H6) is a lightweight Chrome extension designed to help website owners, SEO specialists, content editors, and developers quickly review the structural quality of HTML headings. The extension allows you to paste raw HTML content and instantly analyze the hierarchy of heading tags from H1 to H6. It generates a clear outline, displays heading counts, and highlights common structural issues such as missing H1 tags, multiple H1s, skipped heading levels, or improperly ordered headings. All analysis is performed locally inside the browser using standard web APIs. The extension does not access web pages, does not collect data, and does not require any special permissions. Your content is never transmitted or stored externally. Key features include: Paste-based HTML analysis with no page access Automatic detection of H1–H6 heading structure Visual heading outline for quick review Summary statistics for each heading level Warnings for common hierarchy mistakes Clean, professional user interface Works fully offline with zero permissions This tool is ideal for improving content accessibility, SEO structure, and document clarity before publishing HTML content.