usefulweb.site Accessibility Snapshot

Developer & data tools

Accessibility Snapshot

Static WCAG 2.2 snapshot of a page: findings by severity, evidence and manual checks.

Fetched once, server-side, with the static HTML only (no JavaScript is executed).

Takes precedence over the URL. Useful for pages behind a login or local drafts.

Try an example: Landing page with common problems · Well-structured contact page

How it works

Fetch a public URL or paste HTML to get a deterministic accessibility snapshot: page language, title, image alternatives, form labels, button and link names, heading outline, landmarks, tables, iframes, zoom blocking and more — each finding mapped to a WCAG 2.2 success criterion with the offending element. It also lists what must be checked by hand.

  • The HTML is parsed by a tolerant tokenizer/tree builder; no JavaScript is executed and no CSS is computed, so content injected by scripts is not seen.
  • 28 rules run: language, title, text alternatives, form labels, button/link names, headings, duplicate ids, viewport zoom, data tables, iframe titles, autoplaying media, landmarks, skip link, tabindex and aria-hidden misuse.
  • Each finding is classed as "failure" (strong evidence of a WCAG 2.2 success-criterion failure), "best-practice" (recommended but not a strict failure, e.g. heading order or duplicate ids — SC 4.1.1 Parsing is obsolete in WCAG 2.2) or "needs-review".
  • Accessible names are approximated from aria-labelledby, aria-label, label elements, content text, image alt and title, in that order.
  • Criteria that need rendering or human judgement (colour, contrast, keyboard, focus visibility, captions…) are listed as manual checks.

Automated static checks can only detect some failures. They cannot establish WCAG 2.2 conformance: conformance requires a full manual review of every page state (WCAG 2.2 §5.2), including rendered contrast, keyboard operation and assistive-technology testing.

Sources

For scripts and AI agents

  • JSON API: POST https://a11ysnapshot.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://a11ysnapshot.usefulweb.site/mcp · tool name a11y_snapshot
Example request
curl -s -X POST https://a11ysnapshot.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{…see OpenAPI examples…}'

Related tools

  • Accessibility Fixer – Turn WCAG 2.2 problems in your HTML into concrete code fixes, grouped by effort.
  • Website Change Explainer – Compare two versions of a page and see which changes matter: prices, terms, dates, links.
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