Main checks

  • length and letter or number positions;
  • encoded date and valid days, including the sex indicator;
  • expected municipal-code structure;
  • final check character;
  • omocodia forms, where some digits become letters;
  • the eleven-digit temporary tax code with the correct check digit.

Why a regex is not enough

A simple regular expression may accept 31 April or reject a valid omocodia. Validation must interpret parts of the code instead of only looking at their shape.

Formally valid does not mean belonging to the person.

CF Ready does not query the Italian Revenue Agency and does not certify identity, existence or ownership. It reduces input errors before the order closes.

How checkout uses the result

The check runs inside Shopify’s Validation and returns a message only when the merchant’s rule requires it. Codice Fiscale is not stored on CF Ready servers or sent to external providers.

Handling uncertainty

A technical error or an uncertain configuration or plan leaves checkout open. This differs from a field that fails an active rule: in that case, CF Ready shows the configured error.

For the full setup, read how to require Codice Fiscale at Shopify checkout.