Is WCAG 2.1 AA legally required?

WCAG itself is a standard, not a law, but nearly every accessibility law points at it: DOJ ADA settlements, the revised Section 508, EN 301 549 under the EAA, and AODA all reference WCAG 2.0 or 2.1 at level AA. Meeting 2.1 AA (or 2.2 AA) is the practical definition of compliance.

Should I target WCAG 2.1 or 2.2?

Build to 2.2 AA. WCAG versions are backwards-compatible, so 2.2 conformance satisfies every law citing 2.0 or 2.1, and it future-proofs you as regulations update their references.

How much of this checklist can be verified automatically?

Roughly a third of the criteria, but that third covers the majority of failures that occur in the wild: contrast, alt text, labels, ARIA validity, and structure. Keyboard behavior, caption quality, and error-message clarity need behavioral or human testing.

WCAG 2.1 AA checklist, in plain language

WCAG 2.1 Level AA is the conformance level referenced by nearly every accessibility law: the ADA (via DOJ guidance and settlements), Section 508, the European Accessibility Act (via EN 301 549), AODA, and the UK's public-sector rules. This checklist translates its 50 success criteria into checks you can actually act on.

WCAG organizes everything under four principles, POUR: content must be Perceivable, Operable, Understandable, and Robust. Use the checklist below as a working document; each item maps to one or more formal success criteria.

Perceivable: can every user sense your content?

Images need alt text that actually describes them (decorative images get empty alt). Video needs captions; audio needs transcripts. Text must reach a 4.5:1 contrast ratio against its background (3:1 for large text), including text sitting on images and gradients. Content must reflow to a 320px-wide viewport without horizontal scrolling, and nothing may rely on color alone to convey meaning.

Operable: can every user drive your interface?

Everything a mouse can do, a keyboard must do: every link, button, menu, and form control reachable and usable with Tab and Enter, with a visible focus indicator and no focus traps. Skip links let keyboard users bypass repeated navigation. Nothing flashes more than three times per second, time limits are adjustable, and touch targets are comfortably hittable.

Understandable: does the interface behave predictably?

The page declares its language. Navigation stays consistent across pages. Form fields have visible labels tied to their inputs, errors are identified in text (not just a red border), and error messages say which field failed and how to fix it. Nothing unexpected happens on focus or input, like a select that navigates the moment you arrow through it.

Robust: does it work with assistive technology?

Markup parses cleanly, and every custom control exposes its name, role, and value through ARIA correctly. Status messages announce themselves to screen readers via live regions. If you build custom components (dropdowns, modals, tabs), follow the ARIA Authoring Practices patterns or use a library that does.

Compliance checklist

All meaningful images have descriptive alt text; decorative images have empty alt
Videos have captions; audio content has transcripts
Text contrast is at least 4.5:1 (3:1 for large text), including text over images
The page works at 320px width with no horizontal scrolling
Every interactive element is reachable and operable by keyboard alone
Keyboard focus is always visible and never trapped
Forms have programmatically associated labels and text-based error messages
The page language is declared and headings follow a logical hierarchy
Custom widgets expose correct name, role, and value via ARIA
Status updates and validation errors are announced via live regions

Frequently asked questions

Is WCAG 2.1 AA legally required?: WCAG itself is a standard, not a law, but nearly every accessibility law points at it: DOJ ADA settlements, the revised Section 508, EN 301 549 under the EAA, and AODA all reference WCAG 2.0 or 2.1 at level AA. Meeting 2.1 AA (or 2.2 AA) is the practical definition of compliance.
Should I target WCAG 2.1 or 2.2?: Build to 2.2 AA. WCAG versions are backwards-compatible, so 2.2 conformance satisfies every law citing 2.0 or 2.1, and it future-proofs you as regulations update their references.
How much of this checklist can be verified automatically?: Roughly a third of the criteria, but that third covers the majority of failures that occur in the wild: contrast, alt text, labels, ARIA validity, and structure. Keyboard behavior, caption quality, and error-message clarity need behavioral or human testing.