Psychiatric comorbidity is common in children and adolescents with CHDs. Early recognition and evidence-based treatments are crucial to prevent long-term consequences. To support early identification and reduce stigma, we 1) developed and 2) tested the usability and acceptability of online information material on common mental health disorders targeted healthcare professionals and affected families. Website content was shaped by insights from interviews with healthcare professionals across sectors, parents, and adolescents. Evaluations demonstrated promising acceptability and usability of the first prototype but indicated the need for improvements in specific aspects of content, navigation, and overall aesthetics.