DATEMApp is a mobile app for personal health self-management on iOS and Android. It is designed for patients and individuals, not healthcare providers. DATEMApp uses a local-first architecture: medical data is stored in SQLite on the user device. The company does not operate a central backend to collect clinical data. Optional backup uses the user personal Google Drive AppData folder with scope drive.appdata through OAuth. This design gives users direct ownership and privacy control over their records.