Worked on the keycloak/keycloak repository to enhance composite client role mappings, focusing on both performance and correctness. Leveraged Java and JUnit to implement pre-computation of effective roles using breadth-first search, reducing latency for getCompositeClientRoleMappings and improving accuracy in composite resolution. Unified mapping semantics across user and group models with new utility methods, and expanded integration test coverage to ensure robust behavior across multi-client and nested configurations. Migrated tests to the latest framework, improved documentation, and addressed code quality issues, resulting in a more maintainable backend. Emphasized API development, backend optimization, and comprehensive testing throughout the project.