Companies increasingly integrate Artificial Intelligence (AI) into their applications to stay competitive. However, the efficient and successful development and deployment of AI applications requires complex setups. Providing developers with all the required resources, applications, and services for developing and deploying AI applications without reinventing the wheel remains challenging. Therefore, we propose a domain- and workflow-agnostic reference architecture (RA) for an on-premises AI Platform that supports teams throughout the entire AI lifecycle and is reusable across multiple projects. Additionally, we present an evaluation strategy to validate the RA.