WCAGWeb Content Accessibility Guidelines

In plain English

WCAG is the rulebook for building websites and apps that everyone can use — including people who are blind or low-vision, deaf or hard of hearing, have limited motor control, or navigate without a mouse. It's maintained by the World Wide Web Consortium (W3C), the same body behind the core standards of the web, which is why it's the reference point for accessibility law and policy around the world.

Rather than a vague "make it accessible," WCAG gives specific, testable success criteria — like "text has enough contrast against its background" or "every function works with a keyboard."

The four principles (POUR)

Perceivable	People can perceive the content — e.g. alt text for images, captions for video, sufficient contrast.
Operable	People can operate the interface — e.g. everything works by keyboard, nothing traps focus, enough time to act.
Understandable	Content and controls are clear and predictable — readable text, consistent navigation, helpful errors.
Robust	Content works reliably with assistive technologies like screen readers, now and as tech evolves.

Conformance levels: A, AA, AAA

• Level A — the most basic requirements. Missing these blocks whole groups of users.
• Level AA — the practical target for most organizations and the level most laws reference (contrast, focus visibility, consistent navigation).
• Level AAA — the strictest tier; not expected across an entire site.

Most teams aim for WCAG 2.1 or 2.2 at Level AA. WCAG 2.2, published in 2023, adds newer criteria on top of 2.1.

Why it matters

Beyond being the right thing to do, accessibility is often a legal requirement (referenced by the ADA in the US, the European Accessibility Act, and others), and accessible design is simply better design — clearer contrast, keyboard support, and readable structure help everyone. It also overlaps with machine readability: the same clean, well-structured markup that helps a screen reader helps bots read your site.