A CFDI is the electronic invoice Mexico's tax authority, the SAT, validates and seals; version 4.0 has been the only valid one since April 1, 2023. When the recipient has its own Mexican RFC (taxpayer ID), three fields must match what the SAT has registered under it: name, tax regime and postal code.
In short
- For a recipient with its own RFC, name and postal code must belong to that RFC, or the SAT's error matrix rejects the invoice.
- A company with no Mexican RFC is invoiced under the generic RFC XEXX010101000 and tax regime 616.
- Canceling takes a reason code and, unless exempt, the recipient's approval; silence accepts only the first request.
What a CFDI is and who certifies it
CFDI stands for Comprobante Fiscal Digital por Internet, the digital tax receipt defined in Mexico's Federal Tax Code. Under article 29 the SAT validates each CFDI, assigns its folio and adds its digital seal before it is issued; under article 29 Bis it can authorize private certification providers, the PACs, to do the same.
Invoicing a foreign company: the generic RFC
If your company has no Mexican RFC, the SAT's CFDI 4.0 filling guide (Anexo 20) tells the issuer to use the generic foreign RFC XEXX010101000 and tax regime 616 ("Sin obligaciones fiscales"). Ask your supplier for the XML file.
What CFDI 4.0 checks against the RFC
The recipient's name, tax regime and fiscal address became mandatory with CFDI 4.0, per the SAT's Anexo 20 page. That address is a postal code, not a street, and the filling guide says it must be associated with the RFC on the invoice, like the name; the guide applies that rule to RFCs other than the generic ones. The SAT's error matrix has one error for each mismatch, so the invoice is rejected. The CFDI use code has to correspond with the recipient's tax regime (c_UsoCFDI catalog).
When canceling needs the recipient's approval, and when it does not
Canceling a CFDI takes one of four reason codes from the SAT's cancellation pageand, unless the case is exempt, the recipient's approval:
| Code | Reason |
|---|---|
| 01 | Issued with errors, related to a replacement invoice |
| 02 | Issued with errors, no related invoice |
| 03 | The transaction did not take place |
| 04 | A nominative transaction already covered by a global invoice |
When approval is required, the recipient gets a notice in their Buzón Tributario (the SAT's official mailbox) and has three business days, counted from the day after the request, to respond on the SAT portal or via their certification provider. Silence accepts the first request only; afterwards it blocks the cancellation until the recipient accepts.
The SAT lists cancellations that need no approval, among them invoices to foreign residents, invoices up to one thousand pesos, payroll, egreso and traslado receipts, sales to the general public and cancellations within 24 hours.
What automation checks before stamping
Picture a US-owned distributor with a Mexican subsidiary: a retailer sends its new postal code, the SAT still has the old one under that RFC, and every invoice with the new code bounces until someone copies the code from its constancia de situación fiscal (SAT tax status certificate). That is what automation has to catch before stamping:
- The client shares its RFC or constancia de situación fiscal; a foreign client gets the generic RFC.
- The system checks name, tax regime and postal code against the SAT before generating anything.
- It builds the CFDI 4.0 and stamps it through a PAC.
- It emails the invoice and records whether it is paid, pending or canceled for month end.
Walabi's system stamps CFDI 4.0 through a PAC and closes out the month; automated collections for small businessescovers payments, custom software vs SaaSbuild-or-subscribe, and where to start automating a business in Mexicowhat to automate first.
Past 30 invoices a month, automating makes sense from month one; below that, count last quarter's SAT rejections and the hours spent retyping tax certificates.
For your Mexican operation, the 30-minute call is free, in Spanish, with a person: you leave with a map of what a ready-made system covers, what has to be built and what is not worth it yet.
Frequently asked questions
Can a Mexican supplier cancel an invoice to my company abroad without my approval?
Yes. Invoices issued to foreign residents are on the SAT's list of cancellations that need no recipient approval.
What should you ask a Mexican client for before invoicing them?
The SAT's minimum requirements to request an invoice are RFC, recipient name, tax regime and the postal code of the fiscal address. Copy them from the client's latest constancia de situación fiscal; name and postal code must belong to that RFC.
Does Walabi's system stamp through the SAT or through a PAC?
Through a PAC: Walabi's system stamps CFDI 4.0 with a PAC and closes out the month; the rest is custom work, if it is worth it.
Does your team still type every invoice by hand? See how we build custom software that stamps CFDI 4.0 through a PAC and gets month-end close ready.
