Fitbit is a fitness app that connects to Fitbit activity trackers and can monitor calories burned, steps, distance, and sleep quality. Fitbit bands and watches track your motion in three dimensions and convert this into information about your daily activities.
Connecting the Withings App to Fitbit enables you to export weight data recorded by Withings scales. You can also have the ability to import step data from Fitbit into Withings App using Switch to Withings.