During the last 15 years, the suicide rate has doubled among individuals aged between 15 and 24 years in Argentina. This marks the need to develop new strategies for suicide prevention among this age group. Smartphones have become a good platform to provide evidence-based interventions universally, inexpensively and quickly. In particular, there is a high penetration of these devices locally and an acceptance of this technology among young people. In this article, the theoretical basis, as well as the technical design, and safety aspects used for the development of CALMA are described. CALMA is the frst Spanish tool-based mobile app for smartphones, which interacts with the user providing tools based on dialectical behavioral therapy (DBT) for the management of crisis situations and thus preventing suicide among adolescents and young people. CALMA also provides information, promoting activities aimed to reduce one's vulnerability in order to prevent new crises, and psychoeducational content about suicide and its prevention. The app was designed for teenagers and young people. It is available for free in Argentina since May 2017 and works with Android and iOS.