Definition
The CFDI (Comprobante Fiscal Digital por Internet) is the standard electronic invoice format in Mexico. Every income, expense, payroll, or merchandise transfer must be backed by a CFDI to have fiscal validity before the SAT. It is not just a PDF file. A CFDI is an XML file with a structure defined by the SAT that includes a digital signature guaranteeing its authenticity and integrity.When is it mandatory to issue a CFDI?
Current version: CFDI 4.0
Since January 1, 2022, the mandatory version is CFDI 4.0. Previous versions (3.3, 3.2) are no longer valid for new issuances. The most relevant changes in CFDI 4.0 compared to 3.3:- The receiver’s tax regime is mandatory
- The receiver’s fiscal zip code is mandatory
- The use of
P01as the default value was removed (nowS01is used for the general public) - The receiver’s name must exactly match the RFC registered with the SAT
Basic structure
A CFDI is composed of:- Issuer data — who issues the receipt
- Receiver data — who receives it
- Line items — the goods or services being billed
- Taxes — IVA, ISR, IEPS transferred or withheld
- Complements — additional information depending on the operation type
- Original string + Digital seal — the issuer’s cryptographic signature
- Fiscal digital stamp — the PAC seal that certifies the stamping before the SAT
The UUID (Folio Fiscal) shown in the stamp is the CFDI’s unique national identifier. It is the value the SAT uses to verify the receipt’s authenticity.
What is NOT a CFDI?
- The PDF is not the CFDI — it is only a printed representation. The valid fiscal document is the XML.
- A cash register receipt is not a CFDI either, even if it serves as an internal sales note.
- An email with the amount of a service has no fiscal validity without the corresponding stamped XML.