# Accessibility Snapshot

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

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://a11ysnapshot.usefulweb.site/ (interactive tool at https://a11ysnapshot.usefulweb.site/tool)
- JSON API: POST https://a11ysnapshot.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://a11ysnapshot.usefulweb.site/api/v1/tool)
- OpenAPI: https://a11ysnapshot.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://a11ysnapshot.usefulweb.site/mcp - tool `a11y_snapshot`

## Inputs
- url (url): Page URL - Fetched once, server-side, with the static HTML only (no JavaScript is executed).
- html (textarea): Or paste HTML - Takes precedence over the URL. Useful for pages behind a login or local drafts.
- maxFindings (integer): Max findings listed

## Method
- 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failure), "best-practice" (recommended but not a strict failure, e.g. heading order or duplicate ids — SC 4.1.1 Parsing is obsolete in WCAG 2.2) or "needs-review".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.

## Limits
- 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.