Validation

Validation is built around StandardSchemaV1, the minimal ~standard.validate contract. CreateFormOptions.schema validates the whole form. registerFieldSchema(path, options) or adapter options attach a field-local schema that takes precedence for one field.

const unregister = form.registerFieldSchema('email', {
  schema: emailSchema,
  schemaOptions: { libraryOptions: { mode: 'strict' } },
});

const validEmail = await form.trigger('email');
const validForm = await form.trigger();
unregister();

validateOn accepts change, blur, submit, and manual. manual describes an explicit workflow where you call trigger() yourself; it does not prevent submit validation. Standard Schema issues with paths become field errors, while root issues can be handled as form-level feedback through your UI conventions.

Practical guidance

Keep this page near the source when you build abstractions. The reference describes what the package exposes, while guides show one way to compose those pieces. If a helper hides FieldPathInput, validation triggers, or array rebasing, document that helper with the same precision so future maintainers know whether strings, tuples, or stable keys are expected.