Guided workflow for preparing and filing Mexico's monthly IVA (VAT) return via the SAT Declaraciones y Pagos portal, covering CFDI reconciliation, input tax crediting, retention treatment, and submission of the Declaración Mensual de IVA.
Confirm the taxpayer's identity and obligations before touching any numbers. Verify the client's RFC against their Constancia de Situación Fiscal from the SAT portal, confirm their fiscal regime (e.g. Régimen Simplificado de Confianza — RESICO, Personas Morales, Actividades Empresariales), and establish which months are in scope. Identify any special flags: IMMEX/maquiladora status, consolidated group filing, border zone eligibility (8% rate decree), or EFOS/EDOS blacklist exposure.
Download the complete CFDI XML files for the return period from the SAT portal — both emitidos (sales, type I) and recibidos (purchases, type I). Reconcile the CFDI listing against bank account estado de cuenta to identify unmatched items, cash transactions, or missing invoices. For deferred-payment transactions (MetodoPago = PPD), locate the corresponding Complemento de Pago CFDIs, because IVA is recognised on the payment date, not the invoice date.
Classify every supply on the CFDI register by IVA rate: 16% standard, 8% border zone (if confirmed eligible), 0% tasa cero (basic food, medicine, exports under Art. 2-A LIVA), or exempt under Arts. 9/15/20/25 LIVA. Calculate total IVA trasladado (output IVA on sales) and total IVA acreditable (creditable input IVA on purchases). Apply retention rules: platforms and professional services from individuals attract IVA retention at 10.6667%; professional ISR fees trigger 10% ISR retention. Carry forward any saldo a favor (IVA credit balance) from the prior month's declaration.
Access the SAT Declaraciones y Pagos portal and review the pre-filled Declaración Mensual de IVA proposal that SAT generates from CFDI data. Compare the SAT pre-fill figures against the reconciled IVA worksheet. Correct any discrepancies — SAT's figures may omit PPD Complemento de Pago timing adjustments, self-assessed IVA on imported services, or retentions from non-digital channels. Confirm the filing deadline: the 17th of the month following the period (same for RESICO individuals and general regime).
Submit the Declaración Mensual de IVA through the SAT Declaraciones y Pagos portal using the taxpayer's e.firma (FIEL) or Contraseña (CIEC). If there is IVA a pagar, generate the línea de captura and pay via bank transfer or the SAT payment portal before or on the 17th deadline to avoid recargos (surcharges) and multas (fines). If there is a saldo a favor, decide with the client whether to carry it forward to the next period or request a devolution (refund) via the SAT Devoluciones portal.
Run this workflow in your AI agent
Install the MCP connector once — your agent loads the right skills, works through each phase, and routes to a licensed Mexico accountant for review.
mexico-einvoice
Use this skill whenever asked about Mexico e-invoicing, CFDI (Comprobante Fiscal Digital p
mexico-iva
Use this skill whenever asked to prepare, review, or classify transactions for a Mexico IV
mx-cfdi
Use this skill whenever asked about Mexican CFDI electronic invoicing. Trigger on phrases
mx-vat-return
Mexican VAT return (IVA -- Impuesto al Valor Agregado, Declaracion Mensual) for self-emplo