The literature reveals that borderline personality disorder (BPD) is an important public mental health problem that affects both the patients and their families. Moreover, studies indicate a high prevalence of psychological symptoms and burden in relatives of people with BPD. Therefore, it is necessary to develop useful and accessible interventions specifically addressed to the caregivers. Smartphone interventions with Ecological Momentary Assessment (EMA) and Ecological Momentary Interventions (EMI) offer several potential advantages in this regard.