Web Content Accessibility Guidelines (WCAG) is the international standard, published by the W3C, for making web content usable by people with disabilities. The current published version is WCAG 2.2, organised around four principles — Perceivable, Operable, Understandable, Robust (POUR) — and three conformance levels: A, AA, and AAA.
Why it matters
WCAG is more than guidance: AA conformance is referenced by the European Accessibility Act, by Section 508 in the United States, and by procurement rules across the public sector. Failing to meet WCAG can block sales, attract complaints, and — most importantly — exclude real users who rely on screen readers, keyboard navigation, captions, or high-contrast modes. Accessibility issues also overlap with SEO: the same semantic HTML that helps screen readers also helps crawlers parse your pages.
How to check
- Run an automated audit with a tool like axe-core or Lighthouse — automation catches roughly 30-40% of issues.
- Test the page using only a keyboard: every interactive element must be reachable and have a visible focus state.
- Verify text contrast meets 4.5:1 for body copy and 3:1 for large text.
- Use semantic HTML first; reach for ARIA only when native elements cannot express the role.
- Provide text alternatives for images, captions for video, and labels for every form field.
- Pair WCAG testing with usability sessions involving people who actually use assistive technology.