Overview
WCAG, the Web Content Accessibility Guidelines, is the standard your store is measured against in every audit, settlement, and lawsuit. The specification is long and written for specialists. This page is the store-owner translation: what it is, why version 2.1 AA, and which parts actually decide your risk.
Why this standard is the legal benchmark is covered in Do US online stores legally need ADA compliance?
The four principles
Everything in WCAG hangs off four words. Content must be:
- Perceivable. Users can perceive it: images have text alternatives, text has sufficient contrast, layouts survive zoom.
- Operable. Users can operate it: everything works by keyboard, nothing traps focus, users get enough time to act.
- Understandable. Users can understand it: pages declare their language, forms have labels, errors explain themselves.
- Robust. It works with assistive technology: controls have valid roles and names, so screen readers announce them correctly.
Each principle breaks down into testable success criteria. When an audit cites “1.4.3,” it is pointing at one specific criterion under Perceivable.
Versions and levels, quickly
Version 2.1 (2018) is what courts and settlements cite. Version 2.2 (2023) added a handful of criteria; the differences are in WCAG 2.2 vs 2.1.
Level AA is the target. Each criterion has a level: A, AA, or AAA. Level A alone leaves big barriers unaddressed. AAA is impractical for commercial sites. AA is the level the DOJ adopted for government sites and the level nearly every settlement requires, so it is the practical target for stores.
Where WCAG meets your store
- Product images map to 1.1.1 Non-text Content: meaningful alt text.
- Brand colors map to 1.4.3 Contrast: 4.5:1 for body text, 3:1 for large text. The walkthrough is color contrast in Shopify themes.
- Menus, drawers, popups map to 2.1.1 Keyboard and 2.1.2 No Keyboard Trap.
- Add-to-cart and icon buttons map to 4.1.2 Name, Role, Value: every control announced by name.
- Checkout forms map to 3.3.1 and 3.3.2 Labels and Errors: labeled fields, errors that say what went wrong and where.
- Theme typography maps to 1.4.4 Resize Text and 1.4.10 Reflow: usable at 200% zoom, no horizontal scrolling at mobile widths.
That short list covers most of what lawsuits cite and most of what audits find. The overlap with the common failures list is not a coincidence: stores fail the same handful of criteria everywhere.
Example
Criterion 1.4.3 says text needs 4.5:1 contrast against its background. On your store that cashes out concretely: the light-gray shipping note (#999999 on white, about 2.8:1) fails; darkening it to #6b6b6b (about 5:1) passes. Most WCAG criteria reduce to small, checkable decisions exactly like this one. The standard feels abstract until you map it to specific pixels, and then it becomes a checklist.
Common mistake
Treating WCAG as a one-time checklist to “pass.” The criteria describe properties your store must keep having. Every new app, theme update, and banner is a chance to lose one, which is why verification is periodic rather than permanent. The working order for getting there is in the step-by-step compliance guide, and the maintenance habit matters as much as the initial push.