tldr: Accessibility testing checks that people using assistive technology can use your app. It is part legal obligation, part product quality. Automated tools catch about a third of issues; the rest needs a keyboard, a screen reader, and human judgment.
What accessibility testing is
Accessibility testing verifies that an interface works for users with visual, motor, auditory, or cognitive disabilities. That means keyboard operation, screen reader output, sufficient color contrast, and clear focus states.
It is not a niche concern. The same fixes that help a screen reader user (real labels, logical structure, keyboard support) make the product better for everyone.
WCAG and ADA basics
The Web Content Accessibility Guidelines (WCAG) are the standard. They are organized under four principles: content must be perceivable, operable, understandable, and robust. Most teams target WCAG 2.1 or 2.2 at the AA level.
The legal weight comes from regulations like the ADA in the US and the European Accessibility Act. They increasingly reference WCAG AA as the bar, which is why compliance and accessibility testing overlap.
Manual vs automated
Automated scanners are fast and belong in CI, but they only catch the machine-detectable issues: missing alt text, low contrast, absent form labels. Studies put that at roughly a third of real problems.
The rest needs people. Can you complete the flow with the keyboard alone? Does the screen reader announce state changes? Is focus order sane? Those questions do not have a scanner answer.
Tools
Common automated tools include axe, Pa11y, Lighthouse, and WAVE. They integrate into pipelines and pull requests to catch regressions early.
For manual passes, the toolkit is a keyboard and a screen reader: NVDA or JAWS on Windows, VoiceOver on macOS and iOS, TalkBack on Android. Testing with the actual assistive tech beats simulating it.
Running it in CI
Wire an automated scanner into the build so new violations fail fast. Gate on the rules you can trust and triage the rest rather than blocking on noise.
Pair the automated gate with scheduled manual audits on critical flows. Bug0 can run accessibility checks as part of end-to-end coverage on every release, capturing evidence an auditor can review later. See compliance testing and the product-specific BrowserStack accessibility testing page for related angles.
FAQs
Can accessibility testing be fully automated?
No. Automated tools catch roughly a third of issues. Keyboard and screen reader testing by a human is required for the rest.
What standard should we target?
WCAG 2.1 or 2.2 at AA level is the common bar, and it is what most accessibility regulations reference.
Which tools should we start with?
Add axe or Lighthouse to CI for the automated layer, then test critical flows manually with a keyboard and a screen reader like NVDA or VoiceOver.
Does accessibility overlap with compliance?
Yes. Regulations like the ADA reference WCAG, so accessibility evidence often feeds directly into compliance audits.