The use of serious games as educational tools for healthcare professionals and patient interventions is rising, offering potential cost savings and quality improvements in healthcare. Customers from healthcare/educational organizations often ask about clinical effectiveness of these games. However, Dutch developers of games for health, mostly small/medium-sized enterprises (SMEs), lack the resources/expertise for longitudinal research. Simultaneously, SMEs unknowingly demonstrate various validity types during game development. The lack of language to articulate one's own expertise in a way that is understandable for healthcare customers, causes SMEs to miss assignments and fewer promising games reaching healthcare. Our goal is to help developers effectively integrate validity into their processes to deliver acceptable evidence to customers. This abstract outlines our initial project phase, focusing on (game)development processes, validation, and customer collaboration and communication.