Product platforms has been a successful enabler for efficient mass customization. However, they cannot fully support suppliers working in an engineer-to-order business environment. This work identifies the need and scope of a different platform model that supports customization and management of fluctuating requirements. A novel plaform model is introduced entitled Design Platform. The model is based on the current state and future target condition at four companies. The model provides a coherent environment for heterogeneous design assets to be used in product development.