Building and sustaining a successful platform business remains one of the biggest challenges in the age of digitalization and platformization, particularly in the manufacturing industry. The art of managing the partner ecosystem to create and distribute mutual benefits depends on the design of the platform – thus, on the implemented mechanisms and functionalities, typically complemented by third-party applications. Therefore, it is eminently important to attract potential partners to enter the ecosystem. With this article, we provide substantial insight into the case of an emerging platform and its respective ecosystem of stakeholders. We analyze their individual requirements, abstract them into general key requirements, and finally develop design principles. Thus, our research, on the one hand, extends the current knowledge of platform literature with new, generalized knowledge about platform design, especially in the development phase. On the other hand, we contribute to the emerging field of participant attraction previously focusing on complementors.