What Is Web Accessibility?
Quick Definition
Web accessibility (a11y) is the practice of designing and building websites that can be used by everyone, including people with disabilities such as visual, hearing, motor, and cognitive impairments.
Web accessibility ensures that websites and applications work for the widest possible audience, including the estimated 1.3 billion people worldwide who experience significant disability. It covers a range of impairments: visual (blindness, low vision, color blindness), auditory (deafness, hard of hearing), motor (inability to use a mouse, limited dexterity), and cognitive (dyslexia, attention disorders, memory limitations).
The Web Content Accessibility Guidelines (WCAG) are the international standard for web accessibility. They're organized around four principles (POUR): Perceivable (content must be presentable in ways all users can perceive), Operable (UI components must be operable by all users), Understandable (information and operation must be understandable), and Robust (content must be robust enough for diverse user agents and assistive technologies).
Practical accessibility measures include proper heading structure, alt text for images, keyboard navigation support, sufficient color contrast, form labels, ARIA attributes for complex widgets, captions for videos, and responsive design that works with screen magnification.
Accessibility is increasingly a legal requirement. The ADA (Americans with Disabilities Act), European Accessibility Act, and similar laws worldwide require digital services to be accessible. Lawsuits against inaccessible websites have increased dramatically in recent years.
Why It Matters
Beyond legal compliance, accessibility improves the experience for all users. Captions help people in noisy environments, high contrast helps in bright sunlight, and keyboard navigation helps power users who prefer not to use a mouse.
Accessible websites also tend to be better structured, which improves SEO, performance, and maintainability. Google rewards many of the same practices that accessibility requires — proper headings, descriptive links, alt text, and semantic HTML.
Real-World Examples
A retailer faced an ADA lawsuit over their inaccessible website, costing $100,000 in legal fees — fixing accessibility issues cost a fraction of that
A government website improved their WCAG compliance from AA to AAA and saw a 20% increase in form completions from all users, not just those with disabilities
A SaaS company added proper keyboard navigation and ARIA labels to their dashboard, enabling a blind user (who happened to be a Fortune 500 VP) to adopt their product
A media company added closed captions to all video content and discovered that 80% of caption users were not deaf — they were watching in environments where they couldn't use sound
Related Terms
Responsive Design
Responsive design is a web development approach that makes websites adapt and display properly across all screen sizes, from desktop monitors to tablets and smartphones.
UX Design (User Experience Design)
UX design is the process of creating products that provide meaningful, relevant, and enjoyable experiences to users, encompassing all aspects of how a person interacts with a product or service.
Progressive Web App (PWA)
A Progressive Web App is a web application built with modern web technologies that delivers app-like experiences, including offline access, push notifications, and home screen installation, directly through the browser.
Alt Text
Alt text (alternative text) is a written description added to an image's HTML code that describes the image's content and function for screen readers and search engines.
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