Worked on enhancing SSL certificate validation error messaging for the google/nomulus repository, focusing on improving user feedback and reducing support tickets related to certificate issues. Developed a feature in Java that delivers precise, exception-based error messages when SSL certificates are invalid, allowing users and support teams to identify specific problems more efficiently. Incorporated both unit and integration tests to cover certificate validity period errors, strengthening the reliability of the validation process and preventing future regressions. Applied skills in API development, backend development, security, and testing to ensure that the SSL validation flow provides actionable information during incident triage and troubleshooting.