Worked on the cashapp/misk repository, focusing on backend development and security using Kotlin. Delivered a security hardening update for Slack signing secret handling by trimming whitespace, suppressing sensitive data in logs, and preventing Okio errors from exposing secrets, thereby improving the robustness and audit readiness of the Slack integration. Later, implemented the Transaction Rollback Hooks API, introducing an onRollback callback in transactional sessions to ensure registered functions execute only during rollbacks, not on successful commits. Expanded test coverage across modules to reinforce data integrity and reliability in transactional workflows, emphasizing careful transaction management and database consistency throughout the codebase.