Assistive technology (AT)
AccessibilityDefined term
Assistive technology is the class of software and hardware people use to perceive and operate interfaces: screen readers, magnifiers, voice control, switch access, refreshable braille displays. On the web, AT does not scrape pixels — it consumes the accessibility tree through platform APIs.
This is why accessibility is an interoperability contract rather than a feature. Content that maintains correct roles, names, states, and focus behavior works across AT it was never explicitly tested with, the same way standards-conformant HTML works across browsers.
Deep dive: full analysis with this mechanism →
Browse the glossary
Accessibility6 of 28 terms
- Accessibility treeThe parallel structure a browser derives from DOM, CSS, and ARIA that assistive technology actually reads.Accessibility
- Accessible nameThe single text label assistive technology announces for an element, computed by a W3C-specified algorithm.Accessibility
- Focus orderThe sequence keyboard focus follows through interactive elements — WCAG requires it to preserve meaning and operability.Accessibility
- ARIA roleThe WAI-ARIA attribute that declares what an element is to assistive technology — a promise of behavior, not a behavior.Accessibility
- Assistive technology (AT)Software and hardware — screen readers, magnifiers, switch devices — that consume the accessibility tree to operate interfaces.Accessibility
- Contrast ratio⦿ liveThe WCAG-defined luminance ratio between text and background: 4.5:1 minimum for body text at level AA.Accessibility