Worked on security hardening for API access within the calcom/cal.com repository, focusing on session management and access control. Addressed a vulnerability by implementing an early return mechanism for API requests lacking a valid user session, specifically targeting the Add endpoint to prevent unauthorized data creation. This approach reduced the risk of unauthorized access and aligned with established session-management standards. The solution was developed and reviewed collaboratively, utilizing TypeScript and leveraging expertise in API development. The work improved the handling of invalid sessions in the API request flow, effectively reducing the attack surface and enhancing the overall security posture of the application.