The Robert Koch Institute (federal health institution) and data research company Thryve (mHealth Pioneers GmbH) have developed a smartphone app that collects pseudonymized data from fitness-wristbands or smartwatches on physical activity and pulse. This data is linked to geodata on postal code level and analyzed with AI for possible Covid-19 symptoms, in order to get a better picture of mild and yet undetected cases and to improve epidemiological models.