What are WCAG guidelines?

WCAG (Web Content Accessibility Guidelines) is the international standard for web accessibility, published by the W3C. WCAG 2.1 Level AA is the compliance target for the European Accessibility Act and ADA. It covers 78 success criteria across four principles: Perceivable, Operable, Understandable, and Robust.

The WCAG versions and levels

WCAG 2.0 (2008): The original widely adopted version. Still referenced in many legal contexts but considered outdated.

WCAG 2.1 (2018): Adds 17 new success criteria to 2.0, with specific improvements for mobile accessibility, low vision, and cognitive and learning disabilities. This is the current required standard for European Accessibility Act compliance.

WCAG 2.2 (2023): Adds 9 new criteria, with significant focus on cognitive accessibility and focus visibility improvements. Not yet mandated by most legislation but increasingly referenced in updated guidelines.

WCAG 3.0 (in development): A significant structural overhaul. Not expected to be finalized before 2027 and won’t immediately replace 2.x for legal compliance.

The three conformance levels:

• Level A: Minimum accessibility. Addresses the most critical barriers. Meeting only Level A is insufficient for EAA or ADA compliance.
• Level AA: The standard compliance target for most legislation worldwide. This is what the European Accessibility Act, ADA (via DOJ guidance), and Section 508 require. Aim for this level.
• Level AAA: Enhanced accessibility. Not required and not achievable for all content types, but represents best practice for specific criteria.

The four POUR principles

WCAG 2.1 is organized around four foundational principles. Every success criterion belongs to one of these:

Perceivable: Information and UI components must be presentable to users in ways they can perceive. Users can’t interact with content they can’t perceive — whether because they’re blind, deaf, or rely on different sensory inputs.

Key criteria:

• All non-text content has text alternatives (images, icons, video)
• Captions for audio content
• Content doesn’t rely on color alone to convey information
• Minimum 4.5:1 color contrast for normal text, 3:1 for large text
• Content can be resized to 200% without loss of function

Operable: Users must be able to operate the interface. Not every user has a mouse — some rely on keyboards, switch access devices, eye-tracking, or voice control.

Key criteria:

• All functionality available via keyboard
• No keyboard traps
• Skip navigation links to bypass repeated content
• Users can pause, stop, or control moving content
• Sufficient time to complete tasks

Understandable: Users must be able to understand both the content and how the interface works. Confusing navigation, inconsistent behavior, and unhelpful errors all fail understandability criteria.

Key criteria:

• Page language declared in HTML
• Consistent navigation across pages
• Labels and instructions for user input
• Error identification: specific description of what went wrong
• Error suggestion: where possible, explain how to fix it

Robust: Content must be robust enough that it can be interpreted reliably by current and future assistive technologies. This principle is about technical quality and standards compliance.

Key criteria:

• Valid HTML with no parsing errors
• Name, role, and value programmatically determinable for all UI components
• Status messages programmatically conveyed without receiving focus

How WCAG applies to e-commerce specifically

WCAG was written as a general web standard, but e-commerce creates specific challenges not explicitly addressed in the guidelines:

Custom UI components — product carousels, variant pickers, filter systems, quick-view modals — are all JavaScript-driven and must have ARIA roles, states, and properties applied correctly to meet robustness criteria.

Dynamic content — price updates, inventory changes, cart modifications — must be announced to screen reader users via ARIA live regions to meet perceivability criteria.

Third-party integrations — payment providers, review platforms, chat widgets — are part of your checkout experience. Their accessibility failures are your compliance failures from a legal perspective, even if they’re not your code.

Checkout forms — the most scrutinized area of e-commerce accessibility. Every success criterion related to forms, errors, and time limits is directly relevant to your checkout.

What WCAG compliance actually requires

Meeting WCAG 2.1 AA does not mean every user can accomplish every task under every circumstance. It means reasonable accommodations have been made across the four principles so that the broadest possible range of users can use your site effectively.

Conformance requires:

1. All Level A and Level AA success criteria are met (or have documented exceptions with alternatives)
2. The site uses complete pages (partial compliance doesn’t count)
3. Only accessibility-supported technologies are relied upon
4. An accessibility statement is published documenting conformance level

A UX audit includes a WCAG 2.1 AA evaluation that documents your current conformance level, identifies specific failing criteria, and provides a prioritized remediation plan for achieving compliance.

For a complete breakdown, read European Accessibility Act Ecommerce Compliance: Complete Guide for Online Retailers.