Cadence is a HIIT interval timer for iPhone, iPad, and Apple Watch built on one promise: nothing interrupts your workout. No ads, no account — and no paywall can ever appear while a timer runs (a rule enforced by unit-tested code). Full-screen color-coded phases readable from across the room, voice coach, haptics, Live Activities, and a standalone Watch app with live heart rate. New workouts drop weekly. Pay once for lifetime (Family Sharing included), subscribe, or stay free. In 6 languages.