In May 2025, Masaharu Uchiyama focused on enhancing data integrity within authentication flows by updating the User interface in both the supabase/auth-js and supabase/supabase-js repositories. He addressed two targeted bugs by introducing a deleted_at property to support soft-delete scenarios, ensuring that client libraries accurately reflected backend semantics. Using TypeScript and leveraging skills in API integration and interface definition, Masaharu standardized the User data shape across repositories, reducing data-model drift and improving reliability. His work provided a more consistent and testable approach to handling soft deletion, directly supporting robust authentication state management in TypeScript-based frontend environments.