The Americans with Disabilities Act (ADA) requires digital products to be accessible to people with disabilities. In practice, this means websites, apps, and software must work with assistive technologies (screen readers, voice control, keyboard-only navigation, etc.). WCAG 2.1 Level AA is the industry standard. 4 principles: Perceivable (can see/hear content), Operable (can navigate with keyboard), Understandable (clear language, predictable), Robust (works with assistive tech).