According to the World Health Organization, about 1.3 billion people, roughly one in six, live with a significant disability. In addition, older adults, people with temporary injuries and anyone using a phone in bright sunlight also face barriers online. Web accessibility ensures that websites and systems can be used by all of them. It is at once a matter of inclusion, law and business.
What is web accessibility
Web accessibility is the practice of designing and building products that can be perceived, understood and operated by anyone, regardless of visual, hearing, motor or cognitive limitations.
In practice, this means, for example, that a blind user can navigate with a screen reader, someone without the use of their hands can operate everything by keyboard or voice, and a deaf person gets captions on videos.
The four WCAG principles
The main global reference is WCAG (Web Content Accessibility Guidelines), published by the W3C. It is organized around four principles:
- Perceivable: content must be presented in ways everyone can perceive, such as alt text on images and captions on videos.
- Operable: every function must work via keyboard, with enough time and without elements that can trigger seizures, such as intense flashing.
- Understandable: clear text, predictable navigation and error messages that explain how to fix the problem.
- Robust: code compatible with current and future assistive technologies.
Most laws and contracts target level AA of WCAG 2.1 or 2.2.
The legal landscape
In the United States, the ADA has been applied to websites in thousands of lawsuits. In Europe, the European Accessibility Act requires many digital products and services to be accessible from June 2025. Many other countries have similar rules. Therefore, ignoring accessibility is also a legal risk.
Essential web accessibility practices
- Alternative text: describe informative images in the
altattribute. Decorative images should have an emptyalt. - Sufficient contrast: body text needs a minimum contrast ratio of 4.5:1 against its background.
- Keyboard navigation: every interactive element must be reachable with the Tab key and have a visible focus state.
- Semantic HTML: use
buttonfor buttons,navfor menus and headings in hierarchical order. - Form labels: every field needs an associated
label, not just a placeholder. - Clear error messages: say which field has a problem and how to fix it, without relying on color alone.
- Captions and transcripts: for video and audio.
- Resizable text: the layout must work at up to 200% zoom.
- ARIA in moderation: ARIA attributes help with complex components but do not replace semantic HTML.
How to test accessibility
- Automated tools: Lighthouse, axe DevTools and WAVE catch many technical issues.
- Keyboard testing: try using the entire site without a mouse.
- Screen readers: NVDA on Windows, VoiceOver on macOS and iPhone, and TalkBack on Android.
- Testing with people with disabilities: no tool replaces the real experience of assistive technology users.
Automated tools detect only part of the problems. For that reason, always combine them with manual testing.
Benefits beyond inclusion
- Better SEO, since search engines also rely on semantic structure and alt text.
- Higher conversion, because clear forms reduce drop-offs.
- A better experience for everyone, including on mobile and slow connections.
- A stronger brand reputation.
Frequently asked questions
Do accessibility overlay plugins solve the problem?
No. Widgets that promise automatic accessibility do not fix structural code problems and sometimes even interfere with screen readers.
Where should I start with an existing website?
Run an automated audit, fix contrast, alt text and form labels, and then test keyboard navigation.
Conclusion
Web accessibility broadens your audience, improves everyone's experience and reduces legal risk. Start with the essential practices, test with tools and real people, and build accessibility in from the start of every project. If you want to audit your website or make it accessible, WDS Developer can help.
