BackgroundChile has a high prevalence of postpartum depression and a significant treatment gap. Some barriers to postpartum depression care uncover the need for more easily accessible and lower-cost interventions. Chile's high utilization of digital technologies across all social strata and the increased use of pregnancy and parenting apps open the possibility of delivering interventions through mobile devices. Cognitive-behavioral internet-based interventions have proven to be effective in reducing symptoms of depression in high-income countries. However, in Chile, this is an underdeveloped field. This manuscript describes a randomized controlled trial protocol that will examine the feasibility and acceptability of a guided 8-week cognitive-behavioral app-based intervention for Chilean postpartum women with depressive symptoms.MethodA small-scale parallel 2-arms trial will be conducted. Postpartum women with minor or major depression will be randomized to the app-based intervention or waitlist. The primary outcomes are feasibility and acceptability variables, mainly; recruitment and eligibility rates, intervention and study adherence, and participants' intervention satisfaction, use, and engagement. Semi-structured interviews with a sub-sample will provide more information about the participants' experience with the intervention. Women's depression status will be assessed at pre-treatment, post-treatment, and 1-month follow-up. Other secondary outcomes will include participants' perceived social support, mother-infant bonding, and maternal satisfaction and self-efficacy.DiscussionThis will be the first internet-based intervention aimed at reducing postpartum depression symptoms developed and studied in Chile. If the intervention and procedures prove feasible and acceptable, we plan to study its efficacy in a definitive controlled trial. If the intervention demonstrates to be effective, the aim is to implement it within the Chilean healthcare setting.