HTML Accessibility Linter
Heuristically scan HTML for common accessibility problems and report errors and warnings.
About this tool
A heuristic, regex-based accessibility linter for HTML. Paste a snippet or full document and it reports common a11y defects grouped into Errors and Warnings with counts and a pass/fail summary. It's aimed at developers who want a quick sanity check before a deeper audit with tools like axe-core, Lighthouse, or a screen reader.
Frequently asked questions
What accessibility issues does this HTML linter check for?
It flags missing img alt text, skipped or missing heading levels, empty links and buttons, unlabeled form controls, missing lang on <html>, a missing <main> landmark, positive tabindex, placeholder href="#"/javascript: links, and click-handler-only div/span elements.
Is this a full WCAG audit?
No. It's a fast heuristic, string-based linter that catches the most common mistakes. It cannot evaluate colour contrast, focus visibility, dynamic ARIA state, or screen-reader experience, so always pair it with a real audit tool and manual testing.
Why does it report a heading-level jump?
Going straight from an <h1> to an <h3> skips <h2>, which breaks the document outline screen-reader users rely on. Headings should descend one level at a time.