Fill_in is a full-featured form builder where users can create forms with multiple field types, control validation rules, and organize inputs through an editor-first workflow. It is built to support fast iteration, from drafting and updating form structure to sharing live forms for responses, while keeping the UI simple and responsive. The product focuses on practical form use-cases like surveys, feedback collection, and onboarding flows, with an emphasis on reliable data handling, clean UX, and production-ready performance.