Why this page exists
Accessibility Conformance Testing (ACT) Rules are the W3C's standardised, externally verifiable descriptions of how to test a specific accessibility requirement. ACT Rules Format 1.1 became a W3C Recommendation in February 2026. Because the rules are public and each has a stable identifier, a tool that names the rules it implements can be checked by anyone. A tool that says only "we run 90 checks" cannot.
So here is our mapping. It is also available as machine-readable JSON at /api/act-rules, served with open CORS, no authentication, and no rate limit — because a transparency claim you have to ask permission to verify isn't one.
The honest part
We claim zero complete ACT implementations, and we want to be clear about why.
AccessHawk Engine v2.1 analyses the HTML your server sends plus your linked stylesheets. It does not run JavaScript, build a rendered DOM, or compute final styles. Several ACT rules — including the full accessible-name computation that name-related rules depend on — require exactly that. So where we implement a rule's core test, we say partial. Where our check is merely informed by a rule, we say related. Where no ACT rule covers what we check, we say so rather than mapping it to something adjacent to inflate the count.
Three of the rules we cite have since been withdrawn by the W3C — 3ea0c8, e6952f and 5b7ae0, largely because WCAG 2.2 removed success criterion 4.1.1 Parsing. We still run those checks, because duplicate IDs and duplicate attributes still break the label-to-field relationships assistive technology depends on. But we count them separately above rather than in our ACT coverage, and we link them to the archived rule text rather than to a page that no longer exists.
Two engines that would let us claim more — Alfa (MIT) and IBM Equal Access (Apache 2.0) — are registered in our engine layer and both publish their own W3C implementation reports. Both need a rendered DOM, which means a headless-browser step we have not shipped yet. They are listed as registered, not enabled inside the product, and we will not describe them as part of our coverage until they actually run.
Engines
| Engine | License | Status | Notes |
|---|---|---|---|
| Loading… | |||
Check-to-rule mapping
| Check | Category | WCAG | ACT rule | Implementation |
|---|---|---|---|---|
| Loading the published mapping… | ||||
What this does not mean
Implementing an ACT rule is not the same as complying with the success criterion behind it, and no number on this page should be read as a compliance percentage. Automated testing reliably finds roughly a third of WCAG 2.1 AA failures. Keyboard traps, caption accuracy, reading order in complex layouts, whether alt text is actually correct, and most PDF reading-order problems all need a human. Read the full methodology for what we can and cannot see.
Engine v2.1 · mapping generated live from the running engine. Found an error in our mapping? That's genuinely useful to us — jim@nighthawkmarketing.com.