BACKGROUND: Mobile health (mHealth) is reshaping healthcare delivery, especially in HIV management. The World Health Organization advocates for mHealth to provide healthcare workers (HCWs) with real-time data, enhancing client care. However, in Malawi's Lighthouse Trust antiretroviral therapy (ART) clinic, the nurse-led community-based ART (NCAP) program faces hurdles with data management due to lack of access to electronic medical records systems (EMRS) in the community setting. EMRS are not typically available in differentiated service delivery settings where reliable power and internet are often unavailable. We used human-centered design (HCD) processes to create a mobile EMRS prototype, the Community-based ART Retention and Suppression (CARES) app. CARES aims to simplify workflow for HCWs and improve client care. As part of prototype testing, we explore CARES' feasibility and acceptability from the perspective of NCAP HCWs. METHODS: We conducted in-depth interviews among 15 NCAP HCWs. We used a rapid qualitative analysis approach guided by the Technology Acceptance Models (TAM1 and TAM2). The study complied with the Consolidated Criteria for Reporting Qualitative Research (COREQ). RESULTS: HCWs demonstrated high perceived usefulness for the CARES app to improve healthcare delivery and data management, both of which could facilitate continued and effective use. However, challenges such as app performance, data integration, and system navigation were significant barriers to ease of use, reducing acceptance and current feasibility of scale-up. Despite challenges, HCWs remained optimistic about CARES' potential to enhance NCAP clinical decision-making and data flow in future, likely reflecting organizational expectations for CARES optimization. Beyond the TAM framework, additional themes of consistent staff engagement and considerations for sustainability were identified as critical factors for long-term success. HCWs emphasized the need for continuous training and stakeholder engagement, improved infrastructure, data security protections, and establishing the CARES app and EMRS integration to facilitate CARES' sustained expansion. CONCLUSION: The study findings underscore the importance of HCD for mHealth buy-in. As HCWs were invested in CARES success, they remained optimistic that the app could enhance NCAP services if user experience and app performance improved. Incorporation of HCW feedback could help deliver the promise of CARES, current and future.