Worked on stabilizing data update flows within the Backbase/stream-services repository, focusing on backend development and API integration using Java and Spring Boot. Addressed a critical bug by updating the arrangement update process to ensure that internal arrangement IDs, rather than external IDs, are consistently used when invoking putArrangementById. This required coordinated changes across ArrangementService and related components, propagating the correct identifier through core services and interfaces. The solution improved data consistency and reduced the risk of incorrect updates, enhancing system reliability for arrangement updates across dependent services. The work emphasized careful attention to data integrity and robust backend practices.