Accessibility Testing Is Not a Checklist You Run Once

Automated accessibility scanners are a good first pass. They flag missing alt text, low contrast, and unlabeled form fields in seconds. The problem is that they catch roughly a third of real issues — the rest need a person actually using the interface without a mouse.

What automated scans miss

A scanner can tell you an image has no alt attribute. It can't tell you whether the alt text you wrote is actually useful, or whether a modal traps keyboard focus once it opens.

• Focus order that jumps illogically around the page.
• Custom components (dropdowns, date pickers, tabs) that look right visually but don't expose the correct role or state to assistive tech.
• Content that updates dynamically without announcing the change to a screen reader.

The manual pass that actually catches these

1. Unplug the mouse. Tab through the entire flow. Every interactive element should be reachable, and focus should be visible at every step.
2. Turn on a screen reader (VoiceOver, NVDA, or TalkBack) and complete the core user flow, not just the homepage. Forms, checkout, search — anywhere a user actually has to act.
3. Zoom to 200% and check that content reflows instead of clipping or overlapping.

Where this fits in a QA process

Run automated scans (axe, Lighthouse) on every build to catch regressions cheaply. Reserve manual keyboard and screen reader passes for new components and before major releases, where the cost of a missed issue is highest. Treat WCAG conformance as a baseline, not the finish line — the standard tells you the minimum, not whether the experience is actually usable.