What is WCAG (Web Content Accessibility Guidelines)?

WCAG are the international web accessibility guidelines published by the W3C (WAI). They are structured around four principles: Perceivable, Operable, Understandable, and Robust, each broken down into success criteria across three levels (A, AA, AAA). Version 2.1 Level AA is the legal standard in most regulations, including the RGAA and the European Accessibility Act.