Accessibility (a11y)
The practice of making websites usable by people with disabilities, including those using screen readers, keyboard navigation, or other assistive technologies.
Web accessibility, often abbreviated a11y (where 11 represents the 11 letters between "a" and "y"), is the practice of designing and building websites that can be used by everyone — including people with visual, auditory, motor, or cognitive disabilities. The W3C's Web Content Accessibility Guidelines (WCAG) are the global standard, currently at version 2.2.
The four WCAG principles are: Perceivable (content must be presentable in ways users can perceive), Operable (interface components and navigation must be operable), Understandable (information and operation must be understandable), and Robust (content must be robust enough to be interpreted by a wide variety of agents, including assistive technologies).
For SEO, accessibility and search engine optimization overlap significantly. Many accessibility practices — descriptive alt text, semantic HTML, proper heading hierarchy, descriptive link text, captions on videos, sufficient color contrast — also help search engines understand and rank content. Per a 2023 Moz industry survey, 67% of SEO professionals say accessibility improvements have positively correlated with their organic rankings.
Legal landscape: in the US, the ADA (Americans with Disabilities Act) has been applied to websites through court rulings since 2019; in the EU, the European Accessibility Act (effective June 2025) mandates accessibility for all digital products sold to consumers; similar laws exist in Canada (ACA), Australia (DDA), and the UK (Equality Act 2010). Non-compliance carries real financial risk — ADA website lawsuits averaged $10,000-$50,000 in settlements in 2024 per Seyfarth's annual report.