Accessibility Testing Tools & Techniques

Building an accessible website requires testing — you cannot rely on good intentions alone. Just as you would test a website in multiple browsers to catch rendering bugs, you need to test for accessibility to catch barriers that prevent people from using your site.

Accessibility testing happens at multiple levels:

Automated testing catches roughly 30-50% of accessibility issues. Tools can detect missing alt text, insufficient color contrast, missing form labels, empty links, and incorrect heading hierarchies. They are fast, consistent, and should be your first line of defense. But they have significant limitations — they cannot judge whether alt text is meaningful ("image123" passes automated tests but is useless), whether keyboard navigation makes logical sense, or whether content is actually understandable.

Manual testing catches the issues that automated tools miss. This includes keyboard navigation testing (can you use the entire site without a mouse?), screen reader testing (does the site make sense when read aloud?), cognitive testing (are instructions clear and error messages helpful?), and visual testing (are focus indicators visible, is content readable at 200% zoom?).

User testing with people with disabilities catches the issues that even careful developers miss. Real users have workflow patterns, assistive technology configurations, and expectations that developers may not anticipate. This is the gold standard of accessibility testing, though it is not always possible for every project.

The good news is that you already have powerful testing tools available for free, right in your browser. Let us walk through the most important ones.