Yannis Nadreau developed a mobile app pre-authentication token API for the edificeio/entcore repository, focusing on improving the authentication flow for mobile clients. Using Java and Vert.x, Yannis implemented a GET endpoint that allows mobile applications to securely retrieve pre-authentication tokens from the Carbonio service. The API design emphasized robust error handling and clear failure paths, ensuring predictable and secure responses for clients. This work addressed the challenge of reducing login friction while maintaining a strong security posture. Over the course of the month, Yannis demonstrated depth in backend and API development, delivering a focused, maintainable feature with clear commit traceability.