Accessibility Testing Tools (axe, WAVE, Lighthouse)
Accessibility testing tools such as axe, WAVE and Lighthouse are the best-known automated checkers for testing websites against technical WCAG failures. Among them, axe (Deque) runs as a browser extension and as the axe-core test library, WAVE (WebAIM) visualises problems directly in the browser, and Lighthouse (Google) is built into Chrome DevTools and uses the axe-core engine as well.
In practice
All three tools automatically check things such as missing alt text, contrast values or ARIA errors, but none of them replaces manual testing. A Deque study published in 2021, based on around 300,000 recorded issues, found that automated testing with axe-core detected up to 57% of accessibility problems — considerably more than the 20 to 30% previously assumed across the industry. The remainder requires keyboard testing, screen reader checks and, ideally, feedback from users with disabilities before a website can be called accessible.