Sebastian Ruff focused on stabilizing authentication flows in the better-auth/better-auth repository, addressing a critical OAuth state handling issue within the Expo Authorization Proxy. By refining cookie-based state management, Sebastian ensured OAuth state values were correctly parsed and maintained throughout the authentication process, directly improving reliability and reducing user friction during login. The solution was implemented in TypeScript and leveraged Node.js and React Native, reflecting full stack expertise. Sebastian co-authored the fix, demonstrating collaborative development and attention to code quality. While the work centered on a single bug fix, it addressed a nuanced problem with depth and careful technical consideration.