Heading Structure & Alt Text Checker

This tool parses a page's raw HTML and pulls out two structural things at once: its full heading outline (every H1 through H6, in order) and every image tag, flagging which ones are missing alt text. It runs the check in your browser using the DOM parser built into every modern browser — nothing is sent anywhere.

It's for anyone about to publish or already maintaining a page — a business owner reviewing a page a freelancer built, a marketer auditing an existing blog post, a developer double-checking a template — who wants a quick structural read without opening browser devtools or reading raw HTML by eye.

Heading structure and alt text aren't cosmetic. The H1 is the strongest heading-level signal for what a page is about, a broken heading order makes the page harder to navigate for anyone using a screen reader, and missing alt text leaves images with no description at all for both assistive technology and image search. All three are things this tool surfaces in one pass over a single paste.

How to use this tool

1. Open the page you want to check in your browser and right-click anywhere on it, then choose "View Page Source" (or press Ctrl+U on Windows, Cmd+Option+U on Mac).
2. Select all the HTML shown and copy it.
3. Paste the full HTML into the "Page HTML source" box on this page.
4. Click "Analyze".
5. Check the three summary numbers first — total headings, H1 count (should read exactly 1), and images missing alt text.
6. Scroll the heading outline to see how sections nest under each other, and review the images list for anything flagged, then fix the source page and re-paste to confirm.

When to run this check

It's most useful right before you publish a new page, and again any time you substantially edit an existing one. Content edits are a common way heading order quietly breaks — someone adds a new section as an H2 when it should have been an H3 under the one above it, or a template change ends up duplicating the H1. Running this as a quick pre-publish step catches that before the page goes live, rather than after it's already been crawled.