In the contemporary digital era, the value of adopting agile and user-centric strategies when developing digital solutions is clear. Our research aimed to create a mobile-first, user-centric Sabbath School digital attendance system specifically for Universitas Advent Indonesia. The existing attendance mechanisms were hindered by the inefficiencies of traditional paper-based methods. To address this, we developed a unique single-page application (SPA) optimized for fast load times and continuous user interactions, removing the need for repeated page reloads. Built using Rapid Application Development (RAD) principles and enhanced by iterative processes, this mobile-first SPA is anchored by a strong API, ensuring dependable integrations and reliable data handling. Our new system addresses the drawbacks and environmental issues associated with paper-based attendance. It features real time tracking, versatile status categories (e.g., present, excused, sick, late), and the ability to produce a range of attendance reports. Furthermore, the system supports group-specific attendance records, detailed metrics, easy-to-use scheduling for attendance-centric meetings, and streamlined student group management. Users can also create groups with individual names, locations, and statuses. The introduction of our approach resulted in a marked improvement in efficiency and user satisfaction, significantly surpassing the old paper-based methods. Given its flexible design, the system’s potential uses could extend beyond educational institutions into wider community areas, including churches. Moving forward, research should investigate the many ways this innovative digital tool can be applied, opening up opportunities for various institutions to harness its benefits.