Haptic feedback
A brief physical tap or vibration from the device that confirms an action, marks a boundary, or signals success or failure.
See it
What it is
Haptic feedback is a physical response from a device, usually a short vibration or tap, tied to an interface event. Apple's Taptic Engine is the familiar example, and the iPhone 7 home button is the proof: it does not move at all, and the click your thumb reports is a sideways pulse under the glass arriving at the instant a real press would have.
Use haptics to confirm an action the finger may be covering, mark a boundary while dragging, distinguish success from failure, or add weight to a rare important moment. Keep patterns short and consistent, and pair them with visible feedback so the meaning never depends on touch alone.
The gotcha is buzz fatigue. Vibrating on every tap, scroll step, or incoming update becomes irritating fast and can waste battery. On the web the support story is blunt: the Vibration API works in Chrome on Android, while Safari on iOS does not implement navigator.vibrate at all, so a web app cannot reach the Taptic Engine. People also switch vibration off system-wide, so treat haptics as enhancement, and never use a long or repeating pattern for ordinary confirmation.
Ask AI for it
Add restrained haptic feedback with the Web Vibration API, treating iOS Safari as a no-op since it does not implement it. Feature detect 'vibrate' in navigator, call navigator.vibrate(10) once after a direct user action succeeds, and use [20, 40, 20] only for a failed action that needs attention. Cancel any active pattern with navigator.vibrate(0) when the view closes. Pair every vibration with a visible state change and an aria-live message, expose a Haptics setting that can disable it, and do nothing when the API is unavailable. Never vibrate on hover, scroll, or every keystroke.