Jason Chang developed and modernized user interfaces across the antiwork/flexile and antiwork/gumroad repositories, focusing on cohesive design systems and improved onboarding. He unified settings workflows by centralizing input components and validation using React and TypeScript, enhancing reliability and accessibility. In antiwork/flexile, Jason refactored forms and navigation, integrated equity settings into invoice flows, and standardized date handling with a consistent DatePicker. He also improved developer experience by updating documentation and adding DevOps tooling for smoother local development. His work in antiwork/gumroad included navigation enhancements, dynamic dashboards, and visual polish, demonstrating depth in frontend development, UI/UX refinement, and component-based architecture.