Developed the Client Subscription Management feature for the EnergyMashupLab/eml-cts repository, establishing a foundation for client-level subscriptions and future monetization. The work involved designing and implementing new RESTful API endpoints, defining request and response types, and refactoring existing controllers to improve maintainability and scalability. Java was used for backend development, with a focus on clear data modeling through the introduction of client-specific subscription data classes. No major bugs were addressed during this period, as the primary emphasis was on robust API design and extensible architecture to support efficient client onboarding and flexible subscription management in future iterations.