Colour Contrast Ratio
// Definition
The luminance ratio between text and background, expressed as 1:1 to 21:1. WCAG AA requires 4.5:1 for normal text and 3:1 for large text. Easily measured by automated tools and a frequent fail on marketing sites.
// Related terms
WCAG
Web Content Accessibility Guidelines — the international standard for accessible web content, organised into four principles (Perceivable, Operable, Understandable, Robust). Levels A, AA, and AAA define increasing conformance. Most regulations target WCAG 2.1 or 2.2 Level AA.
Accessibility Audit
A structured review of a product against accessibility standards, combining automated scans (axe, Lighthouse), manual checks, and assistive-technology testing. Automated tools catch roughly a third of issues; the rest need human judgement.
Screen Reader Testing
Verifying an interface works with assistive technology that reads content aloud — VoiceOver, NVDA, JAWS, TalkBack. Catches missing labels, broken focus order, and content visible only to sighted users.
Learn more · Manual Software Testing
Chapter 5 · Lesson 3: Manual Accessibility Checks You Can Do Today