During January 2026, Manuel Schweigert developed a ChatGPT subscription model access feature for the BerriAI/litellm repository, focusing on enabling Pro and Max subscriptions through OAuth Device Flow authentication. He implemented a new messages endpoint and enhanced the responses bridge, allowing seamless integration with existing client workflows and supporting premium access routing. Using Python, Manuel applied his expertise in API and backend development, OAuth authentication, and unit testing to deliver an end-to-end authentication flow. His work addressed the need for monetization and tighter workflow integration, preparing the system for production deployment and laying the groundwork for future subscription-based features.