People living with HIV/AIDS (PLWHA) are disproportionately African American and many report receiving care from informal (unpaid) caregivers, typically friends and family, including emotional and physical support, financial assistance, and health advice. Informal caregiving can lead to increased stress levels, which, in turn, may cause physical and mental health problems in caregivers. This pilot proof-of-concept study examined the feasibility and acceptability of a mobile application (app) designed to reduce caregiver stress. In this prospective mixed-methods study, African American informal caregivers for PLWHA were recruited from a community-based research center and provided with the app. In eight semi-structured interviews, preliminary feedback regarding app utility and recommendations for improvement was provided by caregivers. Subsequently, a feasibility trial was conducted in which caregiver participants (n = 30) were instructed to use the app daily for 4 weeks, and feasibility and acceptability data were obtained. Most of the caregivers in the feasibility trial were female 18/30 (60%) and 100% were African American, with a mean age of 57.6 years (SD = 11.03). The most frequently used app modules were guided journaling, positive affirmations, and inspirational quotes. Overall, the participants were extremely satisfied with the app (96.3%) and reported that they would recommend it to friends and family. Overall, the app was well-utilized and perceived as valuable by this group of informal caregivers of PLWHA. Further research is needed to refine app content and evaluate its effectiveness in reducing perceived stress and caregiver burden.