Web Accessibility Initiative (WAI): What It Is and What It Publishes

What is the Web Accessibility Initiative (WAI)?

The Web Accessibility Initiative (WAI) is the part of the W3C that develops standards, guidelines and learning resources so people with disabilities can use the web. It publishes the Web Content Accessibility Guidelines (WCAG), WAI-ARIA and related specifications, and it runs the working groups that maintain them. W3C announced WAI on 7 April 1997.

What WAI publishes

• WCAG: testable success criteria for web content at levels A, AA and AAA. WCAG 2.2 adds nine success criteria to 2.1 and removes 4.1.1 Parsing. It does not supersede 2.0 or 2.1. WCAG 3 is still an early working draft.
• WAI-ARIA: attributes that describe custom widgets to assistive technology (see ARIA). The ARIA Authoring Practices Guide shows how to apply them to common patterns such as tabs and dialogs.
• ATAG 2.0: guidelines for authoring tools such as CMSs and editors. UAAG 2.0 for browsers and media players is a W3C Note, not a standard.
• WCAG-EM: a method for judging how well a site conforms to WCAG.
• Easy Checks: a short first look at a page, "quick and easy, rather than exhaustive" in WAI's own words.

The work is split across working groups, among them the Accessibility Guidelines Working Group (WCAG), the ARIA Working Group and Accessible Platform Architectures.

How WCAG is organised

Every success criterion sits under one of four principles, known as POUR: perceivable, operable, understandable, robust. Each criterion has a conformance level. Level A is the lowest, AA is the level most accessibility rules and procurement requirements name, and AAA is the highest. Check which WCAG version and level your jurisdiction actually cites. In the EU, the European Accessibility Act has applied to covered products and services such as e-commerce and banking since June 2025.

Example: an accessible tab set

You are building tabs. The APG tabs pattern tells you which roles and states to use and how the arrow keys should move focus. Then WCAG tells you what to verify: for example, criterion 1.4.3 (level AA) requires a text contrast ratio of at least 4.5:1, or 3:1 for large text. Pattern first, criteria second, then a test with a keyboard and a screen reader.

Common mistakes

• Treating WCAG as a one-time audit. Every release can break contrast, focus order or labels.
• Reaching for ARIA first. Use a native HTML element when one exists, and add ARIA only for what HTML cannot express.
• Trusting a tool score as proof of compliance. The Lighthouse accessibility score is a weighted average of automated audits only; manual audits do not affect it.
• Skipping assistive technology. A page can pass checks and still be unusable by keyboard or screen reader.
• Citing the wrong version. WCAG 2.2 does not retire 2.1, so confirm which one a contract or law names.

WAI and testing

Use automated accessibility testing to catch repeatable failures on every build, and manual tests for what tools cannot judge. When a customer asks for evidence, a VPAT reports conformance against WCAG. LoadFocus Page Speed Monitoring runs scheduled Lighthouse audits, which include an Accessibility category, so a deploy that regresses automated checks shows up between manual reviews. For tool choices, read our accessibility testing tools comparison, and see why performance testing should include accessibility. The full list of standards is on the W3C WAI standards page.

FAQ: Web Accessibility Initiative

What is the difference between WAI and the W3C?

The W3C is the standards body for the web. WAI is its accessibility initiative, which develops the accessibility standards and resources.

What is the difference between WAI and WCAG?

WAI is the organisation and its programme of work. WCAG is one of the documents it publishes, the one that defines the success criteria for web content.

Which WCAG version should I follow?

Follow the version your law, contract or customer names. WCAG 2.2 includes all 2.1 criteria except 4.1.1 Parsing, plus nine new ones, so conforming to 2.2 is usually the safer target.

Is WCAG a law?

No. WCAG is a W3C standard. Laws and procurement rules can reference it, and the version and level they require differ by country and sector.

Where should I start?

Run the WAI Easy Checks on a key page, then work through the WCAG success criteria that apply to your components, and test with a keyboard and a screen reader.

Does a good Lighthouse accessibility score mean my site conforms to WCAG?

No. The score only reflects automated audits. Manual checks and assistive technology testing are still needed to claim conformance.