Heading Structure Analyzer

Paste HTML to see the H1–H6 heading outline and flag issues — missing or multiple H1s and skipped levels.

100% Browser-Based • Local Processing

Paste your page HTML

Copy it from your browser’s Elements panel, not from View Source. View Source shows the HTML before JavaScript runs; if your site builds any part of the page in the browser, those headings are missing from it. Right-click the <html> element in DevTools → Copy → Copy outerHTML gives you what a crawler renders. Whole page or one section, either works. Nothing is uploaded, and the parser used here does not load images or run scripts from what you paste.

Outline

The outline a crawler sees

Nesting comes from the numbers, not from where the tags sit. Browsers never implemented the HTML5 outline algorithm, so wrapping a heading in a <section> does not demote it — an H2 inside a section inside another section is still an H2. The tree above is built the way search engines and screen readers build it: document order, level by level.

Headings are read three ways at once, which is why the same structure serves all three: search engines use them to work out topics and sub-topics, answer engines lift whole sections out by their heading when deciding what to quote, and screen-reader users jump between them as their main way of moving through a page. A skipped level is not a penalty — it is a gap in the outline all three of them have to guess their way across.

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Privacy Focused

🔒 Local Processing. Your site data never leaves your device.

Instant Results

🌐 Fully Client-Side. Runs instantly in your browser.

No Signup

⚡ No accounts. No API keys. Just open and use.

Browser Based

🚀 No installs, no crawlers, no site verification.

Overview

What is a Heading Structure Analyzer?

A Heading Structure Analyzer reads your page's HTML and shows the H1–H6 headings as an indented outline, flagging issues like a missing or duplicate H1 and skipped heading levels. A clean heading hierarchy helps search engines, AI engines, and screen readers understand your content's structure, so paste your HTML and fix any gaps.

Headings (H1–H6) are the skeleton of a page: they tell readers, search engines, AI engines, and screen readers how your content is organised and what's most important. A messy hierarchy — no H1, several H1s, or jumping from H2 to H4 — muddies that structure.

This analyzer parses the HTML you paste and lays out the heading outline with warnings for common problems. It runs entirely in your browser, so your markup stays private.

Guide

How to analyze heading structure

Step 1: Paste your page's HTML (or the relevant section) into the box

Paste your page's HTML (or the relevant section) into the box.

Step 2: Read the indented H1–H6 outline of all headings

Read the indented H1–H6 outline of all headings.

Step 3: Review the flagged issues — missing/multiple H1, skipped levels, empty headings — and fix them in your page

Review the flagged issues — missing/multiple H1, skipped levels, empty headings — and fix them in your page.

Details

Why a clean heading hierarchy matters

A well-structured page reads like an outline: one H1 stating the main topic, H2s for major sections, H3s nested under them, and so on, without skipping levels. The analyzer reconstructs that tree from your HTML and flags the issues that commonly break it: no H1 (the page lacks a clear main topic), multiple H1s (ambiguous emphasis — though modern HTML technically allows them, a single clear H1 is the safest, most common best practice), skipped levels like H2 straight to H4 (a gap in the hierarchy that confuses the outline), and empty headings. Good structure helps in three ways at once: search engines use headings to understand topics and sub-topics; AI answer engines parse them to extract and summarise sections (so clear headings improve your chances of being cited); and screen-reader users navigate by heading, so a logical order is an accessibility requirement, not just an SEO nicety. Note that this analyzes the HTML you paste rather than fetching a live URL, because browsers block cross-origin page reads. Everything runs locally in your browser. For keyword coverage, use the Keyword Density Analyzer.

Support

Frequently Asked Questions

What does a heading structure analyzer do?

It parses your page's HTML and displays all the headings (H1 through H6) as an indented outline showing their hierarchy, then flags structural problems — like a missing H1, more than one H1, skipped levels, or empty headings — so you can fix the page's organisation for SEO, AI parsing, and accessibility.

Should a page have only one H1?

A single, clear H1 stating the page's main topic is the safest and most widely recommended practice. The HTML5 spec technically permits multiple H1s within sectioning elements, but in practice one H1 avoids ambiguity for search engines and assistive tech. The analyzer flags multiple H1s so you can decide intentionally.

What's wrong with skipping heading levels?

Jumping from an H2 to an H4 (skipping H3) breaks the logical outline — it implies a sub-section with no parent. Search engines and screen readers build a tree from your heading levels, and gaps make that tree incoherent. Keep levels sequential: descend one at a time and don't skip on the way down.

Why can't it analyze a URL directly?

Browsers block one website from reading another site's pages (the cross-origin policy), so a purely client-side tool can't fetch and parse an arbitrary live URL without a server. Pasting the HTML keeps everything local and private — view source on your page (or copy the rendered HTML) and paste it in.

How do headings affect SEO and AI search?

Headings signal the topics and sub-topics of your content. Search engines use them to understand what a page and its sections cover, and AI answer engines parse them to extract and summarise the right passage when answering a question — so clear, descriptive, well-ordered headings improve both ranking clarity and your chances of being cited in AI answers.

Do headings matter for accessibility?

Yes, significantly. Screen-reader users often navigate a page by jumping between headings, relying on a logical H1→H2→H3 order to understand structure and find content. A broken or missing hierarchy makes pages hard to navigate non-visually, so good heading structure is both an SEO and an accessibility best practice.

Is it free, and do I need to sign up?

Yes, it's completely free with no account, no trial, and no limit on how many times you use it. Unlike most SEO suites, there's no login wall — it runs entirely in your browser, so you just open the page and use it.

Is my data private?

Yes. Everything is processed in your browser — whatever you type or paste is never sent to a server. Nothing is stored once you close the tab, so your URLs, content, and site details stay on your own device. That client-side approach is the core difference from cloud SEO tools.

Does it work on mobile?

Yes. It runs in your phone's browser with nothing to install, so you can generate or check markup on Android or iOS. The layout adapts to small screens, though pasting longer code is easier on a desktop.

Does it work offline?

Once the page has loaded, the work runs entirely on your device, so it keeps working without a connection. You only need to be online to open the page the first time — which is also why nothing you enter is uploaded.

Can I copy the output?

Yes. You can copy the generated code or results to your clipboard with one click, ready to paste straight into your site's HTML, CMS, or files. Because everything runs locally, copying is instant with no upload step.

Will this directly improve my rankings or get me into AI answers?

It produces correct, standards-compliant markup that helps search engines and AI engines (Google, AI Overviews, ChatGPT, Perplexity) understand your page clearly — which is a prerequisite for ranking and being cited. But it doesn't directly change rankings or guarantee a rich result or AI citation; those are decided by the engines based on your overall content and authority.

Still have questions?

If you can't find the answer you're looking for, feel free to contact our support team.

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