Fitness App Analytics: Tracking Activation and Retention With Event Instrumentation

The article argues that downloads and registrations fail to show whether users actually experience a fitness app's core value. It proposes measuring activation as a user's first valid workout completed within a defined window after starting onboarding, with the seven-day period presented as an adjustable product choice. A funnel approach is recommended to track where users drop off during onboarding and whether they return for another workout. The author favors workout_completed over button-click events, since a click does not confirm the workout was saved. The piece also outlines a shared event envelope, a starter event taxonomy, and a typed, transport-agnostic TypeScript contract for instrumentation.