SIGN PT - VAT exemption codes

When a line on a Portuguese fiscal document carries 0% VAT, Portuguese law requires an exemption code. In the SIGN PT API, each M-code defined by the Autoridade Tributária e Aduaneira (AT) is mapped to a CAUSE_X enum value.

The exemption code is mandatory on every line that carries 0% VAT — it cannot be omitted. SIGN PT validates that the code is present wherever required.

Exemption codes

Note: SIGN PT validates that the code is technically correct and present where required. Choosing the appropriate code for the underlying transaction is the taxpayer's responsibility.

Request example

To add a VAT exemption to a line item, set content.operation.entries.data.vat type to VAT_EXEMPTION and provide the appropriate code:

"vat": {
  "type": "VAT_EXEMPTION",
  "code": "CAUSE_8",
  "reason": "IVA — regime de isenção"
}

The reason field is optional — SIGN PT auto-fills it with the standard AT invoice mention for the given code. Provide a value only to override the default phrasing.