Introduction to E-Invoicing in Mexico

Mexico’s e-invoicing regime is among the most mature and prescriptive mandates globally. For finance and tax teams, success hinges on understanding the technical rails defined in Anexo 20 (the Comprobante Fiscal Digital por Internet or CFDI standard), orchestrating real-time validations with the Servicio de Administración Tributaria (SAT), the Mexican tax administration service, and operating disciplined Accounts Payable (AP) intake and verification processes. This article distills the current rules so you ensure compliance in Mexico with the e-invoicing mandate with confidence.

Overview of Electronic Invoicing in Mexico

Mexico’s e-invoicing system represents a clearance model, with direct sharing of the “cleared” invoice with buyers. Invoices must be sent in the correct XML format to the SAT to be validated and cleared. Once cleared, the final invoice is sent back to the seller to share with their buyer in PDF format. This ensures that the SAT, issuer and recipient all have the same data and can validate this data between each party. From this perspective, the system is simple. However, when it comes to the details, things get far more complicated. It is required for all transaction types and for all taxpayers in Mexico, with only some exceptions. A full understanding of the system is, therefore, needed to ensure e-invoicing and tax compliance.

Legal Framework and Scope of E-Invoicing Regulations

CFDI version 4.0, the Mexico e-invoicing format and system, and latest CFDI version, is mandated by the Código Fiscal de la Federación (CFF). Article 29 requires taxpayers to issue electronic invoices over the internet (CFDI) using SAT-defined technical specifications and a Certificado de Sello Digital (CSD). Article 29-A lists required invoice contents and allows the SAT to define technical rules (Anexo 20). Article 28 & 30 cover accounting records and retention. SAT’s portal consolidates the current CFF text, and Article 30 requires keeping accounting at the authority’s disposal (the five-year archiving rule is part of Article 30’s text as published in official compendia).

SAT’s Anexo 20 and guides (published on the SAT portal) are the operative technical standards for XML structure, catalogs, and processing.

What changed with CFDI 4.0 Compliance (and what it means for B2B)

CFDI 4.0 is the latest version of the required format and has been mandatory since 1 April 2023. It tightened data quality and identity controls. Notable impacts for B2B issuers and AP recipients include:

• Receiver identity fields are stricter: RFC, Nombre/Denominación Social (legal name exactly as SAT’s registry), RégimenFiscalReceptor and DomicilioFiscalReceptor (postal code) are mandatory and validated against SAT catalogs.
• The Timbre Fiscal Digital (TFD) 1.1 remains the mandatory complement certifying the invoice (adding required fields such as UUID, SelloSAT, NoCertificadoSAT, FechaTimbrado). SAT publishes the XSD and the XSLT for the TFD’s cadena original.
• SAT’s Guía de llenado for Anexo 20 is the authoritative reference for field semantics, catalogs, and examples.

Technical Model for Issuing the CFDI (Outbound)

When considering how to technically comply with the Mexican mandate, there are a few aspects to consider. These will factor into whether to create your own solution or choose a certified service provider. Whichever technical solution is used, it needs to comply with the following procedures for CFDI issuance:

Step A: Obtain and safeguard CSDs

Issuers must generate and manage a Certificado de Sello Digital distinct from the e.firma, the general Mexican electronic signature. SAT’s procedures (CertiSAT Web) and user manuals outline how to request, download, and recover CSDs. Controls should include key custody, rotation, and revocation workflows.

Step B: Issue Invoice XML per Anexo 20

Generate the CFDI strictly per Anexo 20 schemas and catalogs. Ensure that the solution follow SAT’s technical documents for the “generación de sellos digitales”.

Step C: PAC certification (timbrado)

Before an invoice is valid, an SAT-authorized PAC (authorized certification provider) must validate structure/catalogs and append the TFD 1.1 with the UUID and SelloSAT. SAT’s TFD pages provide the XSD and cadena original sequence used in the signature workflow. The result is a timbrado CFDI (signed XML) that is legally valid.

Step D: When Complements are Required for E-Invoicing Compliance

Certain transactions require complementos in addition to the base CFDI. Two common B2B cases are:

• Complemento de pagos 2.0 (Recibo electrónico de pago, CFDI type “P”) when consideration is not paid in a single instalment. It must be issued no later than the 5th day of the month following the payment. SAT’s own guides warn that missing this deadline may trigger CFF infringements.
• Complemento Carta Porte 3.1 for the transport of goods by participants in logistics chains; SAT’s Carta Porte rules and guides define scope and printed-representation requirements.

Step E: Issued CFDI Electronic Invoice

Once the above process is complete and the invoice is validate by the CFDI, it should be returned from the solution to your systems in order to be shared with your buyers. It should be in PDF format with an embedded QR code. This is the legal invoice that must be shared with buyers.

Accounts-Payable (Inbound) Validation: What “good” looks like

For AP invoices, standard validation practices should be in place with your technical solution to ensure that the invoices received have been cleared by the SAT. This will, in turn, ensure that you can reclaim any VAT on these invoices without risk of penalties. There are a two methods for this validation. The first is to use SAT’s ConsultaCFDI web service to query the invoice by the “expresión impresa” (the combination of fields: RFCs, total, UUID). The SAT documentation states the service is designed for high-volume, real-time checks (with capacity up to 2 million queries/hour), though the SAT warns against unnecessary load. However, this is a manual process and is time-consuming for the user, even if the system can handle high-volumes. The alternative is to use a mass retrieval and reconciliation solution, which can pull all XML and/or metadata you have emitted/received, using e.firma credentials.

Another aspect to consider is Complementos. If the invoice is credit-based or paid later, your AP process must expect a Payments complement (CFDI type “P”) and match it to the underlying invoice(s). SAT’s guide details field mapping and the 5-day rule.

Cancellation Rules and Timelines 

Mexico uses a controlled cancellation flow rather than a standard credit note system. Many CFDI require receiver acceptance to cancel. If the receiver does not respond, the SAT applies afirmativa ficta after 3 business days in subsequent attempts (acceptance by lapse). Teams should note this timeframe in supplier and AP portals. The SAT provides “consulta de CFDI relacionados” web services (for PACs) to understand relationships (e.g., credit notes, substitutions). While AP solutions do not call this service directly, understanding these relationships helps in three-way match and fraud prevention. In 2025, the Suprema Corte (SCJN) declared unconstitutional the policy limiting cancellations to the same year, which is relevant for disputes and historical cleanup. Compliance teams should review internal SOPs and vendor terms to align with the new jurisprudence.

XML and Signature Regulations in Mexico

The core structure of the CFDI is an XML per Anexo 20 for clearance at the SAT. Attributes and nodes must follow SAT catalogs and rules. Issuers must provide the cadena original (canonical string) and sign with a CSD private key. The SAT’s documentation covers generation rules. After a PAC validates and “timbras” (signs), it inserts the TimbreFiscalDigital complement with the UUID and SelloSAT derived from the SAT’s certificate.

Timeframes and Useful Operational SLAs

E-Invoicing Issuance / certification

Timbrado is an online process executed by a PAC against SAT requirements. Design your integrations or choose a partner that can handle near-real-time certification and gracefully retry if the PAC is temporarily unavailable. (Technical basis for the certification workflow and TFD in SAT specs.)

AP status verification

SAT’s ConsultaCFDI supports very high throughput (up to 2M invoices/hour as per SAT documentation). Due to its capacity, it is suggested to use it on receipt and again prior to payment for invoices at risk (e.g., those subject to supplier disputes). Furthermore, it must be used prior to filing for VAT recovery.

Payment Complements Regulations in Mexico

If you receive goods/services on credit, expect the Payments CFDI no later than the 5th day of the month following each payment. Missing complements are a red flag before releasing funds.

Cancellation Accept/Reject Compliance in Mexico

Build AP workflows that track the 3-business-day window for cancellation requests requiring acceptance and update payables holds accordingly.

Overall, it is important to ensure that the technical solution chosen can provide the relevant pre-validations using the CFDI schema, where possible, to reduce the risk of errors encountered with the tax office as well as to validate AP data in an automated, scalable manner to reduce compliance burdens. This help to ensures e-invoicing compliance in Mexico.

Recordkeeping, Archiving and Audits

The retention of invoice data is mandatory in Mexico. It is required to keep the original XML of every issued and received CFDI and its complements as part of your accounting records under CFF Article 30. Evidence of timbrado, ConsultaCFDI responses, Descarga Masiva logs, and cancellation workflows to substantiate transactional history must be maintained. Where required (e.g., Carta Porte), SAT rules stipulate additional fields in printouts. If this is applicable, the printed layouts would need to align with the official Instructivo de llenado referenced in the Resolución Miscelánea Fiscal.

Consequences of non-compliance

Mexico has implemented strict penalties for non-compliance with e-invoicing requirements. Non-compliance can result in the following penalties being charged:

1.       SAT imposes a fine of MXN $400.00–$600.00 per CFDI that lacks required complements as set by general rules.

2.       A fine ranging from MXN $880.00 to MXN $17,030.00 may be imposed for failure to provide documentation covering the transportation of goods.

3.       A fine ranging from MXN $19,700.00 to MXN $112,650.00 may apply for not issuing, delivering, or making available CFDI documents online to clients as required by tax provisions; issuing them without meeting regulatory requirements; not providing the printed version of the CFDI when requested by clients; not issuing internet-based CFDI covering transactions with the general public; or not making these documents available to tax authorities upon request.

4.       A fine of MXN $19,050.00 to $108,880.00 applies for issuing a CFDI with an RFC that does not match the actual buyer or user of the goods or services.

Beyond fines, the SAT may temporarily restrict CSDs under CFF Article 17-H Bis, effectively blocking your ability to invoice until you clarify or remediate the cause via the SAT’s procedure. In certain cases of repeated offences, the Tax Code allows the Mexican tax authority (SAT) to close businesses where violations occur. Non-compliance with CFDI regulations may also constitute tax fraud or smuggling under Mexican law.

Conclusion

The Mexican e-invoicing mandate is well-established and extensive, covering all transaction types and all VAT-payers. Having a robust technical solution for the issuance of CFDI 4.0 compliant invoices, as well as the validation of AP invoices received, is essential to avoid significant penalties. CFDI compliance isn’t just “generate an XML and get a stamp.” It’s a disciplined lifecycle: master-data governance, strict Anexo 20 conformance, real-time certification, robust AP validations (ConsultaCFDI and Descarga Masiva), and airtight archiving. eezi, Powered by VAT IT, can easily provide you with such a solution, which conveniently also gives you access to e-invoicing solutions globally, with only one integration. Contact us for more information on how we can get you compliant and seamlessly streamline your invoicing and tax processes.