The prevalence of depression is high after childbirth: rates of postpartum depression (PPD) are as high as 25% among women without prior PPD or depression but with personal or structural risk factors such as being low- income or a women of color, among others. As such, the American College of Obstetricians and Gynecologists recommends screening women for PPD. However, disparities in postpartum mental health care exist: <60% of women attend post-partum visits where PPD screening occurs, and barriers such as lack of transportation or childcare have been shown to not only reduce rates of postpartum visit attendance but to disproportionately affect low-income women or women of color. In addition, the risk of PPD extends beyond 60 days post-partum, when pregnancy-related federal health insurance often expires. Smartphone applications (apps) may increase equity in postpartum mental health by providing long-term access to mental health treatment to most women. Indeed, in the United States, 96% of those aged 18-29 own a smartphone, and medical apps have been shown to improve obstetric outcomes and increase access to mental health services. Though in-person, cognitive behavioral therapy given through the Mothers and Babies Program (MB) has been shown to reduce PPD by 53% among low-income women of color, the effect of app-provided group MB is unclear. The purpose of this Mentored Patient-Oriented Career Development Award (K23) is to enable the candidate to develop a funded research program to optimize postpartum mental health care for low-income women of color via an innovative technology-based intervention that may decrease their rates of PPD. To achieve this goal, training and mentor- ship are proposed in three key areas: 1) Advanced training in mixed methods research, perinatal psychology, digital health, and biostatistics; 2) Mentorship from a multi-disciplinary team of established researchers; and 3) Protected time to perform patient-oriented research on the feasibility of utilizing app-provided MB as a study intervention for low-income women of color with risk factors for PPD. Two study phases are required. First, focus groups and interviews will optimize the study intervention, which contains MB and parenting education (PE). Those in the intervention group will access MB+PE while those in the control group will access PE to encourage app engagement with both study groups. This is because women in both groups will receive bimonthly Edinburgh Postnatal Depression Scales (EPDS) scores from birth to six months postpartum. The primary outcome of the proposed randomized trial is demonstrated feasibility and acceptability of app-based MB, defined via recruitment and app usage (feasibility), and scores on the System Usability Scale and Client Satisfaction Questionnaire (acceptability). Secondary outcomes include EDPS scores. The proposed trial will provide critical insight into a subsequent R01-supported randomized trial designed to examine the effect of app-based MB on PPD among low-income, racially and ethnically diverse women. If effective, app-based MB has great potential for scalability and could increase postpartum mental health equity for most women.