During March 2026, Edgar Bellot Mico focused on backend development and testing for the mattermost/mattermost repository, addressing a critical bug in the guest magic link authentication flow. He implemented atomic token consumption using Go, ensuring that guest authentication tokens are single-use and eliminating the risk of token reuse due to a race condition. By aligning the guest login process with existing SSO token handling patterns, Edgar improved both the security and reliability of guest onboarding. His work demonstrated a strong grasp of API development and concurrency control, resulting in a more robust authentication mechanism for Mattermost’s guest users.