PAC (Mexico)

In Mexico, it is the PAC that turns a plain XML into a tax-valid invoice on behalf of the SAT.

Definition

A PAC (Proveedor Autorizado de Certificación) is a Mexican authorised certification provider. It is a private company licensed by the SAT to certify e-invoices (CFDIs) on behalf of the tax administration.

The PAC acts as the trusted third party in Mexico's clearance e-invoicing model.

Role

When it receives a CFDI signed by the issuer, the PAC:

• validates the XML structure and compliance with SAT rules;
• checks the issuer's signature and digital seal certificate (CSD);
• stamps (timbra) the document, adding the SAT seal, timestamp and the unique UUID;
• forwards the certified CFDI to the SAT and returns it to the issuer.

Good to know

Without going through a PAC, a CFDI has no tax validity: the PAC stamp is the document's condition of validity.

Several PACs compete in the market; businesses and their accounting software freely choose their provider, which typically charges per transaction or per volume of stamps.