Since 2018, the D.O.T. (die offene Tür – the open door) research group at the Karl Landsteiner Private University has been working on complex interventions to strengthen social cohesion and the mental well-being of children and young people. The research group emerged from a Citizen Science project by the Ludwig Boltzmann Society and has already been able to develop various offers for young people, together with the target group itself. One of the applications that has been developed is the Online Peer Encouragement Network (O.P.E.N.). This is an anonymous online platform for exchange between trained, supervised young people who seek help with their personal problems or who are simply looking for someone of their own age to talk to. By directly involving the target group in the development of the platform, it was ensured that the application meets the needs of users. An example of this adaptation is the design of O.P.E.N. as a hybrid form of chat and e‑mail, which combines a familiar form of communication with the advantages of asynchronous dialogues. Through O.P.E.N., low-threshold access to support services for young people is created. Initially, there is an opportunity for them to exchange information with trained peers in a protected environment; if necessary, they can then be referred to higher-threshold psychosocial support services. O.P.E.N. thus supports the development of transition psychiatry through its own services to referral to other psychosocial service providers in the test region of Lower Austria.