Why Accessibility Matters — and What WCAG Actually Is

Accessibility (abbreviated a11y — 11 letters between the a and y) is the practice of building products that people with disabilities can use. This is not a niche concern: the World Health Organization estimates over 1.3 billion people live with some form of disability. On the web, that means tens of millions of people are unable to use your product unless you build it correctly.

Disability categories that affect web use

• Visual — Blindness, low vision, colour blindness, photosensitivity. Users rely on screen readers, zoom, high contrast mode, or avoid flashing content.
• Motor — Limited hand movement, tremors, paralysis. Users rely on keyboard-only navigation, switch access, eye tracking, or voice control (Dragon NaturallySpeaking). They cannot use a mouse.
• Cognitive — Dyslexia, ADHD, memory impairments. Users need clear language, predictable layouts, sufficient time, and error recovery.
• Hearing — Deafness, partial hearing loss. Users need captions for video, transcripts for audio, and no sound-only notifications.
• Situational and temporary — A broken arm, bright sunlight on a screen, holding a baby with one hand, slow connection. Accessibility features help everyone in these moments.

WCAG 2.2 — the four principles (POUR)

• Perceivable — Information must be presentable in ways all users can perceive — alt text for images, captions for video, sufficient colour contrast.
• Operable — UI components and navigation must be operable — keyboard accessible, no seizure-inducing flashes, enough time to complete tasks.
• Understandable — Information and UI operation must be understandable — plain language, consistent navigation, error identification and suggestions.
• Robust — Content must be robust enough to be interpreted by assistive technologies — valid HTML, ARIA used correctly, current standards.

Conformance levels

WCAG defines three levels: A (minimum), AA (standard), and AAA (enhanced). Most laws and regulations require AA compliance. Aim for AA as your baseline — AAA is aspirational and not required by most legal standards.

Legal requirements

• ADA (USA) — The Americans with Disabilities Act has been interpreted by courts to apply to websites. Companies have lost lawsuits — Domino's Pizza reached the Supreme Court over inaccessible web ordering.
• EAA (European Union) — The European Accessibility Act comes into force June 2025 for private companies operating in the EU. Non-compliance is a legal risk, not just a moral one.
• EN 301 549 (public sector) — The EU standard for public sector digital services — referenced in many government procurement requirements globally.
• AODA (Canada), DDA (Australia) — Most developed countries have equivalent legislation. If your product operates internationally, accessibility is not optional.

Assistive technologies overview

• Screen readers — NVDA and JAWS on Windows; VoiceOver on macOS/iOS; TalkBack on Android. They read the DOM aloud and allow keyboard navigation through elements.
• Switch access — Physical switches that send keyboard events. Users navigate by cycling through focusable elements with a single button.
• Voice control — Dragon NaturallySpeaking allows users to click, type, and navigate by voice. Elements need visible, unique labels for voice commands to work.
• Screen magnifiers — ZoomText and OS-level zoom. Users may only see 10% of the screen at a time — layout must be usable when zoomed to 400%.