⚡ WCAG · A11y · Landmarks

Web Accessibility Checker

Scan any page for the accessibility issues that fail Lighthouse audits — heading-order skips, missing main landmark, unlabeled form fields, empty links, missing alt text and low-contrast pairs — each with a plain-language fix.

How does the Web Accessibility Checker work?

It fetches your page’s HTML in your browser and runs the structural checks screen readers depend on: document language and title, a main landmark, exactly one H1, heading levels that never skip, labels on every form field, accessible names on buttons and links, alt text on images, real link destinations, and a best-effort contrast check on inline styles.

  1. Enter a URL — any public page.
  2. Read the score — pass/warn/fail across ~10 structural checks.
  3. Fix the fails first — landmarks and heading order move Lighthouse the most.
  4. Label every control — inputs, icon buttons, image links.
  5. Verify contrast in Lighthouse — rendered-page contrast needs computed styles.

What are the most common accessibility failures?

Four issues cause most failed Lighthouse accessibility audits: heading levels that skip (h2 straight to h4 — often a footer’s h5), no main landmark, form fields without labels, and text contrast under 4.5:1 — classically white text on light greens or ambers. All four have one-line fixes shown in the table below.

IssueOne-line fix
Heading order skips (h2→h4)Demote to the next level (h4→h3); footer h5s become styled <div>s
No main landmarkWrap content in <main id="content">…</main>
Unlabeled form fields<label for="id"> or aria-label on every input/select/textarea
Low contrast textDarken text until the ratio ≥ 4.5:1 (white-on-#12996B = 3.35 fails)
Links that rely on colourUnderline links inside content so colour isn’t the only cue

Frequently asked questions

Screen-reader users navigate by headings the way sighted users scan a page — a skipped level (h2 straight to h4) breaks that outline like a missing chapter. It’s also a Lighthouse audit, so fixing skips directly raises your accessibility score.
<main> marks where the actual content starts, letting assistive-tech users jump past the navigation with one keystroke. Without it Lighthouse fails the “document has a main landmark” audit. One <main> per page, wrapping everything between header and footer.
Footer column titles don’t need to be headings at all — convert them to styled <div class="foot-h"> elements with the same CSS. They keep the exact look but leave the heading chain, which fixes the order-skip on every page at once.
Partially — it computes ratios for elements whose inline styles declare both text and background colours. Full contrast auditing needs the rendered page with computed styles, so pair this scan with Lighthouse’s accessibility audit for complete coverage.
WCAG AA requires 4.5:1 for normal text and 3:1 for large text (18px bold / 24px+). Watch white text on brand colours — white on #12996B green is only 3.35:1 and fails; darkening the green to #0B6B4A passes at ~6.9:1.
No single automated tool is — automation catches roughly a third of WCAG issues. This covers the structural checks that fail most Lighthouse audits; combine it with keyboard-only testing and a screen reader for the rest.

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