Eugen focused on backend authentication and documentation improvements across homarr-labs/homarr and keycloak/keycloak. In homarr, he enhanced OIDC sign-in observability by implementing detailed logging and JSON-stringified debug data for user and profile objects, which streamlined troubleshooting and improved security monitoring. His technical approach leveraged JavaScript and TypeScript to capture error causes and enrich traceability during authentication flows. Later, in keycloak, Eugen improved deployment documentation by updating AsciiDoc files and container templates, making onboarding and deployment more consistent and maintainable. His work demonstrated depth in authentication, backend development, and technical writing, with careful attention to maintainability and operational clarity.