Personal tool that copies my own Fitbit wellness data into intervals.icu.
FitBitSync is a private, single-user script. It reads my own health data from the Google Health API and writes it to my own training log at intervals.icu, so resting heart rate, heart rate variability and sleep appear alongside my training data.
Only its author. The app is not offered to anyone else, has no sign-up, and stores no data belonging to other people.