a11yhat

An open-source WCAG 2.2 accessibility machine, structured the way the work is organized — by the four principles, Perceivable · Operable · Understandable · Robust (POUR). One crew in the hardHats family (hardHats is the framework; a11yhat is a crew built with it).

How it works

Each principle is a crew lead — a module that owns its success criteria. Every applicable criterion gets a recorded result; nothing is silently skipped:

• PASS — checked and met.
• FAIL — checked and failed, with the specific elements.
• CHECK — a representative measurement ran; a human must confirm the rest (keyboard operation, caption quality, reading order — anything a parser can't judge alone). Each CHECK names the exact thing to look at.
• NA — not present on this page.

Shared foundation: dom.py (a dependency-free DOM), color.py (WCAG luminance), base.py (the uniform Finding record and the Crew base).

Install & run

pip install a11yhat            # once on PyPI
python -m a11yhat page.html    # full POUR report, exit 1 on any FAIL
python -m a11yhat page.html --json
cat page.html | python -m a11yhat -

Grounding

Criteria, topics, and pass/fail conditions follow the DHS Trusted Tester for Web (5.1.3) process. Standard library only — nothing is installed into your environment. Automated checks catch the machine-decidable failures; the CHECK items are the ones a tester must confirm, each with the exact thing to review. It is an honest tool: it does the fast 80% and tells you precisely what the human 20% is — it does not pretend a scanner can certify a page.

License

MIT. Copyright Vincent Gonzalez / F-Keys Creative LLC.

Tests

python -m unittest discover -s tests — every deterministic check is proven to catch its defect and to clear on good input, and a clean page produces zero failures.