Technological developments can optimize therapy for depression. However, early client or user involvement is crucial. The smartphone application and dashboard ‘plaTfOrm using evidence-based inTervEntions for (Mental) health’ (TOTEM), based on cognitive behavioral therapy and behavioral activation, is being developed together with clients from the start. Objective monitoring (e.g., activity/travel-related behavior) and human-in-the-loop AI machine learning allow tailored blended care, combining face-to-face therapy with online modules and Just-in-Time Adaptive Interventions. As a first co-creation step, clients with (prior) depression or depressive complaints and psychologists evaluated the usefulness of an existing Health for Travel Behaviour (HTB) application and feedback report developed for cardio patients, which monitors and improves travel-related physical activity. Online semi-structured interviews followed an HTB demonstration. In total, 16 interviews (14 clients and 2 psychologists) were transcribed and analyzed. Participants perceived the application as user-friendly, relevant, useful, attractive, and a supplement to standard care. It encourages people to engage in activities. The feedback report was also perceived as transparent, useful, and relevant. Emotional aspects are underemphasized (e.g., assessment of feelings and mental health-related psycho-education). When tailored to depression (with attention for different recovery phases), monitoring and improving travel-related physical activity was considered helpful in supplementing standard care for depression.