During February 2026, Duncan Lutz focused on backend development for the spruceid/sprucekit-mobile repository, addressing a critical issue in Credential JWT Serialization. He resolved a bug that previously caused JWT payloads to be double-encoded, ensuring payloads are now correctly represented as raw byte arrays. Duncan applied Rust to implement robust serialization logic and introduced comprehensive end-to-end tests to validate JWT handling across multiple credential formats. Collaborating closely with Ryan Tate, he coordinated the pull request review and merge process. This work improved the reliability and security of credential processing, demonstrating depth in Rust, backend systems, and test-driven development.