Form Handling and Data Validation Questions

Assess form implementation across user experience and system boundaries. Cover client side and server side validation strategies, input sanitization and protection against injection, cross field validation and error aggregation. Evaluate state management approaches for forms, including controlled and uncontrolled patterns, debouncing, optimistic updates and persistence of partial state. Review accessibility of form controls and error messaging, testing strategies for validation logic, and edge cases such as file uploads and international input formats. Discuss how validation decisions affect security and user experience.