Worked on the checkmarble/marble-frontend repository to deliver new API endpoints supporting decision data retrieval by score and rule execution distribution by status. Focused on API design and development, the work involved updating OpenAPI specifications and simplifying the decision data DTO by removing non-required fields, which reduced payload size and streamlined data shapes for frontend integration. Leveraged YAML for OpenAPI spec updates and data modeling to ensure accurate documentation and alignment between frontend and backend. These enhancements improved the readiness of the frontend for data-driven analytics and made the API more maintainable by clarifying response structures and reducing unnecessary complexity.