Worked on the Backbase/stream-services repository to implement upsert functionality for portfolio trading accounts, enabling both creation and updating of accounts linked to investment portfolios. The approach focused on enhancing the service layer for more reliable trading account data handling and introduced robust error handling to ensure data integrity during upsert operations. Addressed asset patch requests by enabling the setting of new values and resolved related unit test failures, aligning changes with the project changelog and coordinating fixes with the team. Utilized Java, RESTful API design, and the Spring Framework to deliver backend improvements that support faster onboarding and improved reliability.