What is CFDI and how does Mexico's e-invoicing system work?
CFDI (Comprobante Fiscal Digital por Internet) is Mexico's mandatory e-invoicing standard administered by the SAT (Servicio de Administracion Tributaria). All Mexican taxpayers (businesses and individuals) must issue CFDIs for sales, wages, and other transactions. Each CFDI is submitted to the SAT via a PAC (Proveedor Autorizado de Certificacion), which validates and seals the document with a unique digital stamp before the invoice is delivered to the buyer.
How is a CFDI generated and certified?
CFDI workflow: (1) Taxpayer generates the invoice in XML format (CFDI 4.0 schema); (2) XML is sent to a PAC (authorized certification provider) via API; (3) PAC validates the XML against SAT rules (schema, tax calculations, RFC validity); (4) PAC sends the validated XML to the SAT and receives a UUID (Folio Fiscal) and digital seal (Sello Digital); (5) PAC returns the sealed CFDI to the taxpayer; (6) Taxpayer delivers the CFDI XML and PDF representation to the buyer. The UUID is the primary legal identifier; invoices can be verified on the SAT verification portal.
Frequently Asked Questions
- What is a PAC and how does a business choose one?
- A PAC (Proveedor Autorizado de Certificacion) is a private company authorized by the SAT to certify CFDIs. Businesses can choose any SAT-authorized PAC for CFDI certification services. Key selection criteria include: API reliability and uptime, pricing (per-CFDI certification fees), ERP integration capabilities, support for complementos (CFDI supplements for specific industries), and portal features for invoice management and status tracking. The SAT publishes a list of authorized PACs on its website.
- What are CFDI complementos and when are they required?
- CFDI complementos are mandatory XML supplements that extend the base CFDI with additional data required for specific transaction types. Common complementos include: Nomina (payroll), Carta Porte (transport documents for goods in transit), Comercio Exterior (foreign trade), Pagos (payment receipts linking payments to invoices), and Leyendas Fiscales (tax legends). The Carta Porte complement became mandatory in 2022 for all goods transport operations within Mexico, similar to Brazil's DANFE requirement.