How do I install the Mexico Einvoice skill?

Run npx skillmds@latest add openaccountants/mexico-einvoice in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Mexico Einvoice skill do?

> Use this skill whenever asked about Mexico e-invoicing, CFDI (Comprobante Fiscal Digital por Internet), SAT (Servicio de Administración Tributaria), PAC (Proveedor Autorizado de Certificación), timbrado (digital stamping), Anexo 20, CFDI version 4.0, XML schema for Mexican invoices, UUID/folio fiscal, RFC validation, complemento de pago, carta porte, nomina, cancelación de CFDI, or any question about generating, validating, certifying, or troubleshooting Mexican electronic invoices. Also trigger when advising on SAT compliance, PAC selection, XML structure, fiscal regime codes, product catalog codes (c_ClaveProdServ), or CFDI workflow. ALWAYS read this skill before touching any Mexico e-invoice work. It is listed under AI & ML on SkillMD.

Is Mexico Einvoice safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Mexico Einvoice?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Mexico Einvoice free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under AGPL-3.

Who published Mexico Einvoice?

openaccountants (@openaccountants) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Mexico Einvoice by openaccountants — Agent Skill

Name: Mexico Einvoice
Author: openaccountants

Mexico CFDI E-Invoice Skill v1.0

General reference only. This skill is general tax/accounting reference material for AI-assisted workflows. It has not been reviewed for any specific person's facts, documents, elections, deadlines, residency, filing status, or local procedures. Do not rely on it to file, pay, amend, or take a tax position without review by a qualified professional in the relevant jurisdiction.

Section 1 -- Quick Reference

Field	Value
Country	United Mexican States (Mexico)
Currency	MXN (Mexican Peso); multi-currency supported with exchange rate
E-Invoicing System	CFDI (Comprobante Fiscal Digital por Internet)
Governing Body	SAT (Servicio de Administración Tributaria)
Key Legislation	Código Fiscal de la Federación (CFF) Art. 29, 29-A; Resolución Miscelánea Fiscal (RMF)
Technical Standard	Anexo 20 Version 4.0
Schema Format	XML (W3C compliant)
Current Version	CFDI 4.0 (mandatory since 1 January 2023)
Certification Model	Three-party clearance: Taxpayer → PAC → SAT
Implementation Status	Most mature e-invoicing system in the Americas; mandatory for all taxpayers since 2014
Taxpayer ID	RFC (Registro Federal de Contribuyentes)

Key Dates

Event	Date
CFDI inception	2004 (CFD); 2011 (CFDI mandatory for large)
Universal mandate	1 April 2014 (all taxpayers)
CFDI 3.3	1 July 2017
CFDI 4.0 published	1 January 2022
CFDI 4.0 sole valid version	1 January 2023
Platform real-time access mandate	1 May 2026 (Art. 30-B CFF, platforms must give SAT real-time data access)

Section 2 -- Mandate Scope

Who Must Comply

ALL taxpayers in Mexico (personas físicas and personas morales) who carry out economic activities
No threshold — every transaction requiring a tax receipt must produce a CFDI
Applies to: sales of goods, services, leases, payroll, donations, exports, imports

Document Types (TipoDeComprobante)

Code	Type	Description
I	Ingreso	Income invoice (standard sales/services)
E	Egreso	Credit note / refund
T	Traslado	Transfer of goods (no payment)
N	Nómina	Payroll voucher
P	Pago	Payment receipt (Complemento de Pago)

Complementos (Supplements)

Complemento	Use Case
Pagos 2.0	Payment receipts for deferred/partial payments
Carta Porte 3.1	Bill of lading for goods transport
Nómina 1.2	Payroll details
Comercio Exterior 2.0	Export invoices
INE	Political party donations
Hidrocarburos	Oil & gas sector

B2C Treatment

B2C sales use RFC genérico: XAXX010101000 (domestic) or XEXX010101000 (foreign)
Still requires full CFDI generation and PAC certification
Simplified "factura global" available for aggregating small B2C transactions (daily/weekly/monthly)

Section 3 -- Technical Format

XML Schema

Aspect	Detail
Format	XML
Version Attribute	Version="4.0"
Root Element	`<cfdi:Comprobante>`
Primary Namespace	http://www.sat.gob.mx/cfd/4
XSD Schema	cfdv40.xsd
Timbre Fiscal Schema	TimbreFiscalDigitalv11.xsd
XSLT (cadena original)	cadenaoriginal_4_0.xslt
Catalogs XSD	catCFDI.xsd
Encoding	UTF-8

CFDI Lifecycle

Taxpayer ERP/System → Generate XML → Sign with CSD (e.firma) →
Submit to PAC → PAC validates → PAC stamps (timbrado) →
PAC returns UUID + TimbreFiscalDigital → Invoice valid →
PAC transmits copy to SAT

Digital Certificates

Certificate	Purpose
e.firma (FIEL)	General identity certificate (not for signing CFDI directly)
CSD (Certificado de Sello Digital)	Specifically for signing CFDI; obtained from SAT portal
PAC Certificate	PAC's own certificate for the timbrado (fiscal stamp)

Cadena Original

The "cadena original" is a pipe-delimited string of all significant invoice fields, generated via XSLT transformation. The taxpayer's digital seal (sello) is a SHA-256 + RSA signature of this cadena original.

Section 4 -- Mandatory Fields

Comprobante (Root) Attributes

Attribute	Description	Format/Values
Version	Schema version	"4.0"
Serie	Series identifier	1-25 alphanumeric
Folio	Sequential number	1-40 alphanumeric
Fecha	Issue date/time	AAAA-MM-DDThh:mm:ss
FormaPago	Payment form code	c_FormaPago catalog (01=Cash, 03=Transfer, 99=Por definir)
SubTotal	Subtotal before tax	Decimal
Moneda	Currency code	c_Moneda catalog (MXN, USD, EUR, etc.)
TipoCambio	Exchange rate (if not MXN)	Decimal
Total	Total amount	Decimal
TipoDeComprobante	Document type	I, E, T, N, P
Exportacion	Export indicator	01=No export, 02=Definitive, 03=Temporary
MetodoPago	Payment method	PUE (single payment) or PPD (deferred/partial)
LugarExpedicion	Issuing postal code	5-digit Mexican postal code
Sello	Digital seal (signature)	Base64-encoded RSA signature
NoCertificado	CSD certificate number	20-digit string
Certificado	CSD public certificate	Base64-encoded X.509

Emisor (Issuer)

Element/Attribute	Description
Rfc	Issuer RFC (12 or 13 chars)
Nombre	Legal name (must match SAT records exactly)
RegimenFiscal	Fiscal regime code (c_RegimenFiscal catalog)

Receptor (Receiver)

Element/Attribute	Description
Rfc	Receiver RFC (or XAXX010101000 for generic B2C)
Nombre	Receiver legal name (must match SAT records)
DomicilioFiscalReceptor	Receiver's fiscal postal code (must match SAT records)
RegimenFiscalReceptor	Receiver's fiscal regime code
UsoCFDI	Purpose of CFDI (c_UsoCFDI: G01=Acquisition, G03=Expenses, etc.)

Conceptos (Line Items)

Attribute	Description
ClaveProdServ	SAT product/service catalog code (8 digits)
NoIdentificacion	Internal product identifier
Cantidad	Quantity
ClaveUnidad	Unit of measure code (c_ClaveUnidad)
Unidad	Unit description
Descripcion	Item description
ValorUnitario	Unit price
Importe	Line amount (Cantidad × ValorUnitario)
ObjetoImp	Tax object (01=No tax object, 02=Yes taxed, 03=Yes not taxed, 04=Yes partially)

Impuestos (Taxes)

Path	Description
Concepto/Impuestos/Traslados/Traslado	Tax transfer per line
@Base	Taxable base
@Impuesto	Tax code (002=IVA, 003=IEPS)
@TipoFactor	Tasa (rate), Cuota (fixed), Exento (exempt)
@TasaOCuota	Rate value (0.160000 for 16% IVA)
@Importe	Tax amount
Impuestos/TotalImpuestosTrasladados	Document-level total transferred taxes
Impuestos/TotalImpuestosRetenidos	Document-level total retained taxes

Timbre Fiscal Digital (Added by PAC)

Attribute	Description
Version	"1.1"
UUID	Folio fiscal (36-char UUID) — the unique invoice identifier
FechaTimbrado	PAC stamping timestamp
RfcProvCertif	PAC's RFC
SelloCFD	Taxpayer's seal (repeated)
NoCertificadoSAT	SAT certificate number used by PAC
SelloSAT	PAC/SAT digital seal

Section 5 -- Transmission Method

PAC Certification (Mandatory)

Aspect	Detail
Role	PACs validate, stamp, and transmit CFDIs to SAT
Number of Active PACs	~70+ authorized by SAT
Connection	SOAP or REST web services (varies by PAC)
Validation Steps	Structure, catalogs, RFC validation, tax math, CSD validity
Stamping Time	Usually < 3 seconds
Fallback	SAT free portal (portal.sat.gob.mx) for manual low-volume issuance

Communication Flow

Taxpayer system generates CFDI XML (signed with CSD)
Submit to PAC via web service
PAC validates structure + data against SAT catalogs
PAC validates receiver RFC/name/postal code against SAT database
PAC generates UUID (folio fiscal)
PAC applies TimbreFiscalDigital complement (SAT stamp)
PAC returns stamped CFDI to taxpayer
PAC sends copy to SAT within 72 hours
Taxpayer delivers stamped CFDI to receiver

SAT Free Issuance Portal

Available at portalcfdi.facturaelectronica.sat.gob.mx
Limited to low-volume issuance
Requires e.firma (FIEL) login
Not suitable for automated/high-volume scenarios

Cancellation

Rule	Detail
Method	Submit cancellation request via PAC
Receiver acceptance	Required for invoices > MXN 1,000 (receiver has 72 hours to accept/reject)
Motivo (reason)	01=CFDI with errors (related doc exists), 02=CFDI with errors (no replacement), 03=Transaction did not occur, 04=Related to global invoice
Time limit	Same fiscal year or month following issuance
FolioSustitucion	UUID of replacement CFDI (if motivo=01)

Section 6 -- Validation Rules

PAC Validation Sequence

Structural — XML well-formed, conforms to cfdv40.xsd
Catalog codes — All coded fields must exist in SAT catalogs (c_FormaPago, c_Moneda, c_ClaveProdServ, c_ClaveUnidad, c_UsoCFDI, c_RegimenFiscal, etc.)
RFC validation — Receiver RFC must exist in SAT's valid RFC list (LRFC)
Name matching — Receiver Nombre must match SAT records exactly (including accents/capitalization)
Postal code — DomicilioFiscalReceptor must match SAT's registered address for that RFC
Fiscal regime — RegimenFiscalReceptor must match SAT's records
Mathematical — SubTotal = sum of Concepto.Importe; Total = SubTotal + taxes - retentions
CSD validity — Certificate not expired, not revoked, belongs to issuer RFC
Seal verification — Sello matches cadena original using CSD public key

Common Rejection Reasons

Error	Description	Fix
301	XML structure invalid	Validate against cfdv40.xsd
302	CSD expired or revoked	Renew CSD at SAT portal
303	Invalid seal	Recompute cadena original and resign
305	Receiver RFC not in LRFC	Verify RFC exists in SAT database
306	Receiver name mismatch	Use exact name from SAT's constancia
307	Receiver postal code mismatch	Use fiscal domicile postal code
402	Invalid ClaveProdServ	Look up correct 8-digit code in SAT catalog

Section 7 -- Tax Computation Rules

IVA (Value Added Tax)

Rate	Application
16%	General rate (most goods and services)
0%	Basic foodstuffs, medicines, exports
Exempt	Education, residential rent, medical services

IEPS (Special Production and Services Tax)

Applied on specific goods: alcohol, tobacco, fuel, sugary drinks, pesticides
Rates vary by product category

Tax Retention

Tax	Rate	When
ISR retention	10% (general)	Professional services paid to individuals
IVA retention	10.6667%	Services by individuals; transport; temporary staffing

Calculation Rules

Tax base per line = Cantidad × ValorUnitario (before tax)
Tax per line = Base × TasaOCuota
Round to 2 decimal places at line level (6 decimal places for TasaOCuota)
Document SubTotal = sum of all line Importe values
Document Total = SubTotal + TotalImpuestosTrasladados - TotalImpuestosRetenidos
For PPD (deferred payment): taxes recorded in Complemento de Pago at time of actual payment

Multi-Currency

If Moneda ≠ MXN, must include TipoCambio (exchange rate)
All amounts in the CFDI are in the stated Moneda
SAT computes MXN equivalent using the stated TipoCambio

Section 8 -- Archiving Requirements

Requirement	Detail
Retention Period	5 years from date the tax return was filed (CFF Art. 30); effectively 6-7 years
Format	Original signed XML (with TimbreFiscalDigital)
Accessibility	Must be available for SAT audit; queryable from SAT portal
Storage	Electronic; taxpayer's own systems + copy maintained by SAT
PDF Representation	Optional; XML is the legal document; PDF/printed version is courtesy copy
Complementos	Must retain all associated complementos (pagos, carta porte, etc.)
Cancellation Records	Retain cancelled CFDIs with cancellation acknowledgment
Platform Data (from May 2026)	Platforms must provide SAT permanent online access; data archived 5+ years

Section 9 -- Penalties for Non-Compliance

Violation	Penalty
Not issuing CFDI	MXN 17,020 -- MXN 97,330 per event (CFF Art. 83-IV / 84-IV)
Issuing CFDI without fiscal requirements	MXN 17,020 -- MXN 97,330
Not delivering CFDI to client upon request	MXN 17,020 -- MXN 97,330
CSD cancellation by SAT	SAT may cancel CSD for repeated violations (prevents all future CFDI issuance)
Simulated operations (EFOS)	2-9 years imprisonment + fines (CFF Art. 113 Bis)
Acquiring/using CFDI from EFOS	Tax deductions/credits disallowed + penalty
Late cancellation	Administrative fines; SAT may reject cancellation

Receiver Consequences

Receiver who deducts/credits a CFDI that does not meet requirements risks deduction disallowance
ISR deductions and IVA credits require a valid CFDI with correct receiver data

Section 10 -- Interaction with Tax Skills

Monthly VAT Return (Declaración Mensual IVA)

IVA trasladado (output VAT) derived from type "I" CFDIs issued
IVA acreditable (input VAT) derived from type "I" CFDIs received
IVA retenido from retention CFDIs
SAT pre-fills monthly return proposals based on CFDI data

Annual ISR Return

Income declared must match sum of type "I" CFDIs issued in the fiscal year
Deductions must be backed by valid received CFDIs
SAT cross-references reported income vs. CFDI issuance records

Payroll (Nómina)

Payroll CFDIs (type "N" with Nómina complemento) feed into:
- Employee's annual tax return (pre-filled income)
- Employer's ISR withholding obligations
- Social security (IMSS) cross-validation

Complemento de Pago

For PPD method invoices, actual VAT is recognized only when payment CFDI is issued
Cashflow-based IVA timing: VAT liability/credit arises on payment date, not invoice date
Monthly IVA return uses payment CFDIs for deferred-payment transactions

SAT Audit Crossmatching

SAT automatically cross-references buyer-seller CFDI pairs
Discrepancies flagged in taxpayer's "Buzón Tributario" (tax mailbox)
Invitation letters ("carta invitación") issued for unexplained income vs. CFDI mismatches

Disclaimer

This skill and its outputs are provided for informational and computational purposes only and do not constitute tax, legal, or financial advice. Open Accountants and its contributors accept no liability for any errors, omissions, or outcomes arising from the use of this skill. All outputs must be reviewed and signed off by a qualified professional (such as a Contador Público, CPA, or equivalent licensed practitioner in your jurisdiction) before filing or acting upon.

The most up-to-date, verified version of this skill is maintained at openaccountants.com.

Source: OpenAccountants — open tax Guides for AI, reviewed by named CPAs/CAs/EAs. Quality: source-cited draft. For always-current figures and named-accountant backing, connect the OpenAccountants MCP server (openaccountants-mcp).

Mexico Einvoice

File contents