W3C Accessibility Standards Overview


The World Wide Web Consortium (W3C) develops international Web standards: HTML, CSS, and many more. W3C’s Web standards are called W3C Recommendations.

All W3C standards are reviewed for accessibility support by the Accessible Platform Architectures (APA) Working Group.

The W3C standards and Working Group Notes introduced below are particularly relevant to accessibility.

Accessibility Guidelines

Essential Components of Web Accessibility shows how web accessibility depends on several components of web development and interaction working together, and how the WAI guidelines (WCAG, ATAG, UAAG) apply.

Web Content Accessibility Guidelines (WCAG) 2

Web “content” generally refers to the information in a web page or web application, including:

WCAG applies to dynamic content, multimedia, “mobile”, etc. WCAG can also be applied to non-web information and communications technologies (ICT), as described in WCAG2ICT.

WCAG 2 info:

Authoring Tool Accessibility Guidelines (ATAG)

Authoring tools are software and services that “authors” (web developers, designers, writers, etc.) use to produce web content. For example: HTML editors, content management systems (CMS), and websites that let users add content, such as blogs and social networking sites. ATAG documents explain how to:

ATAG info:

User Agent Accessibility Guidelines (UAAG)

User agents include browsers, browser extensions, media players, readers, and other applications that render web content.

UAAG info:

W3C Accessibility Guidelines (WCAG) 3 Working Draft

WCAG 3 is an early draft that is intended to become a W3C Standard. WCAG 3 applies to web content, apps, tools, publishing, and emerging technologies on the web.

WCAG 3 info:

Technical Specifications

Accessible Rich Internet Applications (WAI-ARIA)

ARIA provides semantics so authors can convey user interface behaviors and structural information to assistive technologies (such as screen readers). The ARIA specification provides an ontology of roles, states, and properties that define accessible user interface elements.

The ARIA suite includes API mapping specifications that provide user agent implementation guidance. It also include modules for Graphics and Digital Publishing.

ARIA info:

Audio and Video


The following resources support development of accessibility evaluation methods and tools:

Additional resources related to evaluation are listed in the Evaluating Web Accessibility Overview, including:


WAI-Adapt Overview — WAI-Adapt enables users to adapt (or ‘personalize’) how content is presented to meet their needs and preferences. Content authors can use WAI-Adapt standards to provide a default design and enable user adaptation with minimal work.


Pronunciation Overview — Pronunciation is about screen readers and other text-to-speech (TTS) synthesis pronouncing content properly.

Other Areas of W3C WAI work

Additional Information

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