Developed and delivered a nonce-based message submission security mechanism for the traPtitech/traQ repository, addressing the challenge of duplicate message submissions in concurrent environments. The solution introduced a unique nonce for each message, ensuring idempotent operations and enhancing overall message integrity and security. This backend feature was implemented using Go, with a focus on robust API development and careful integration into the existing messaging flow. The work demonstrated disciplined version control and a security-oriented approach, resulting in improved reliability and trust in the system’s message handling. No major bugs were fixed during this period, with efforts concentrated on this core enhancement.