Accessibility testing combines automated tools with manual checks because automation catches only a fraction of real issues. Tools like axe DevTools, Lighthouse, WAVE, Pa11y, and Accessibility Insights are excellent for surfacing missing alt text, low contrast, missing labels, and duplicate IDs, but they typically detect only about 30 to 40 percent of accessibility problems. Keyboard logic, focus management, reading order, and screen reader behavior all require human judgment. A manual keyboard test navigates the entire UI with Tab, Shift+Tab, Enter, Space, arrows, and Escape, confirming that every control is reachable, every focus state is visible, and every action produces the expected result. A manual screen reader test, using NVDA on Windows, VoiceOver on macOS or iOS, TalkBack on Android, or JAWS in corporate environments, verifies that announcements match intent, focus order is logical, and dynamic updates are exposed correctly. Whenever possible, the best test is still with real users with disabilities, whose lived experience uncovers issues no tool can flag.
Accessibility audits bring these practices together into a structured review of UI patterns, markup, behavior, and testing results, with findings prioritized by user impact so that the most important fixes, those that prevent people from completing core tasks, are addressed first. Building accessibility from the start of design and development, often called shifting left, is dramatically cheaper than retrofitting, while last-minute drive-by fixes tend to be fragile and miss systemic issues. Teams benefit from accessibility personas that describe users with specific assistive technologies and constraints, because designing for concrete profiles reveals requirements that an abstract checklist might miss.
Cognitive accessibility is often overlooked but central to inclusive design. Plain language with short sentences, common words, and active voice reduces cognitive load for users with cognitive disabilities, second-language readers, and stressed users alike. A target reading age around grade six to eight works well for general public content, and tools like Hemingway can help simplify prose. Interfaces should reveal important information by default rather than hiding it behind interactions, because hidden details add cognitive load. WCAG 2.2, finalized in 2023, added criteria on focus appearance, dragging movements, target size minimums, consistent help, accessible authentication, and redundant entry to push this further, while the draft WCAG 3 is moving toward outcome-based scoring with broader scope including cognitive, mobile, and hardware contexts. Inclusive design, as articulated by Microsoft's toolkit and the curb cut principle, frames accessibility as part of designing for the widest range of human variation, recognizing that features originally built for disabled users, such as captions, dark mode, and curb cuts, end up benefiting everyone.