What is web accessibility and why does it matter?

Web accessibility (often written a11y) means building sites that people with disabilities can perceive, understand, navigate and use. That covers visual, hearing, motor and cognitive disabilities, such as blindness, low vision, deafness, tremors or dyslexia.

It also helps people in situational limits: glare on a phone screen, a broken arm, a noisy train or a slow connection. Features built for accessibility often benefit everyone, as captions and keyboard shortcuts show.

Why it matters:

• People: the WHO estimates over a billion people live with some form of disability, so this is a large audience.
• Law: rules such as the ADA, Section 508 and the European Accessibility Act require it in many markets.
• Business: better usability, wider reach and often better SEO.

The basics are cheap when done early:

• Use semantic HTML elements.
• Give images text alternatives.
• Keep color contrast high.
• Make everything usable by keyboard.

Treat accessibility as part of quality from the start, not a late patch.