How does React handle forms at scale?

At scale, React forms face challenges: excessive re-renders (every keystroke re-renders the form), complex validation, nested forms, dynamic fields, and form state that interacts with application state. Strategies: (1) React Hook Form: uses uncontrolled inputs with refs — only re-renders on submit or when validation changes. Provides register, handleSubmit, formState.errors. Performance difference vs controlled: a 100-field form with RHF renders ~3 times on submit vs 100+ times with controlled inputs. (2) Schema validation: integrate Zod or Yup for declarative validation schemas that colocate validation rules with data types. (3) Field-level vs form-level rendering: in Formik/RHF, ensure field components are memoized to prevent full form re-renders on field changes. (4) Nested forms pattern: use React context to share form state across deeply nested custom fields without prop drilling. (5) Dynamic fields: RHF's useFieldArray handles dynamic list fields efficiently. (6) Server validation: use Remix's form actions or React Server Actions (React 19) for forms that interact directly with the server without client-side JavaScript state.