In the twenty-first century, the increasing prevalence of chronic diseases and structural barriers in accessing healthcare services have necessitated a more active role for individuals in managing their own health. This transformation has shifted healthcare from a hospital-centered model toward daily life practices, emphasizing the concept of self-care. Although mobile health (mHealth) technologies offer significant potential in this context, the fragmentation of health data across multiple platforms and privacy concerns associated with cloud-based solutions hinder widespread user adoption. This study presents the design and development of a Mobile Health Tracking System that prioritizes user data privacy through an offline-first architecture and local data storage. The application was developed using the Flutter framework and the Dart programming language to support both Android and iOS platforms. Data persistence is ensured through an on-device SQLite database, preventing the sharing of sensitive health information with third-party servers by default. The system includes essential modules such as Body Mass Index (BMI) calculation, customizable user profiles, medication reminder mechanisms, blood pressure monitoring, heart rate tracking, sleep data management, and interactive health visualizations implemented using the flchart library. System performance was evaluated based on user interface responsiveness, database query execution times, and notification service stability. The results indicate that local database–based mHealth applications provide significant advantages in terms of data privacy, offline accessibility, and user trust. Furthermore, the findings demonstrate that Flutter’s single-codebase architecture offers a cost-effective and high-performance solution for developing cross-platform healthcare applications. Additionally, the application supports the generation of personalized PDF health reports from user data. To mitigate the risk of data loss during device changes, an optional Firebase-based cloud synchronization feature has been integrated, allowing users to back up and restore their data at their discretion.
Yılmaz et al. (2026) studied this question.