The Web Content Accessibility Guidelines (WCAG) are a set of best practices for making web content accessible to people with disabilities. The guidelines are organized around four principle categories: perceivable, operable, understandable, and robust. By following these guidelines, web designers and developers can help ensure that people with disabilities can access and use web content.
WCAG is an international standard published by the World Wide Web Consortium (W3C). The latest version, WCAG 2.1, was released in June 2018. WCAG 2.0 is the most widely adopted standard, however many organizations are beginning to transition to WCAG 2.1. The United States federal government has also adopted WCAG 2.0 as its standard for accessible web content.
There are three levels of conformance with WCAG: A, AA, and AAA. Level A conformance is the minimum level of compliance and is generally considered sufficient for most audiences. Level AA conformance is more stringent and is recommended for larger organizations with more diverse audiences. Level AAA conformance is the highest level of compliance and is generally only achievable by large organizations with significant resources.