What Is the Payment Complement
The payment complement, commonly called the REP (Recibo Electrónico de Pago, or Electronic Payment Receipt), is a type "P" CFDI that Mexico's tax authority (SAT) requires whenever an invoice isn't paid at the moment it's issued. Instead of modifying the original invoice, the payment complement records each payment received — date, amount, payment method, and remaining balance — without touching the income CFDI that was already stamped.
It became mandatory alongside the CFDI scheme itself and today it operates under CFDI 4.0, which tightened validation of the recipient's data across every voucher type, the REP included. If you're not yet familiar with the basics of a Mexican electronic invoice, it's worth starting with what a CFDI is before digging into the payment complement specifically.
When the Payment Complement Is Issued
Whether a payment complement is required at all depends on the payment method declared on the original invoice:
- PUE (single-exhibition payment): the customer pays at or before the moment the CFDI is issued. No REP is needed here — the invoice already reflects full payment.
- PPD (installment or deferred payment): the customer will pay later, in one or several installments. In this case, a REP is mandatory for every payment received, until the balance is fully settled.
In practice, any credit sale, deposit, partial payment, or collection date that falls after the invoice date triggers the obligation to issue a payment complement. If a business collects cash and invoices the same day, the REP simply doesn't apply.
SAT's Deadline for Issuing the REP
Under rule 2.7.1.32 of Mexico's Miscellaneous Tax Resolution (Resolución Miscelánea Fiscal), the payment complement must be stamped no later than the fifth calendar day of the month immediately following the month in which the payment was received. If that day falls on a weekend or non-business day, the deadline moves to the next business day.
An example makes the rule concrete: if a customer pays a PPD invoice on August 20, the corresponding REP must be issued by September 5 at the latest. It doesn't matter whether the payment lands mid-month or near month-end — the reference point is always the calendar month the money was received, not the date of the original invoice.
Issuing the REP after this window doesn't erase the obligation, but it does expose the issuer to SAT flagging it as a late CFDI, with the risk of compliance notices or the recipient's deduction being challenged if the delay becomes a pattern.
Payment Complement 2.0: What Changed
Payment complement version 2.0, in effect since January 1, 2022 and mandatory since April 1, 2023, replaced version 1.0 (which had operated since 2017-2018) to align the voucher with the logic first introduced in CFDI 3.3 and later carried into CFDI 4.0. The most relevant changes versus the earlier version are:
- "Totales" node: automatically sums the amounts of every payment documented in the same REP, and SAT validates that this sum matches exactly the amounts declared in each individual payment.
- Tax-object flag per payment: each related payment must state whether the amount is subject to tax, mirroring the logic CFDI 4.0 requires on income vouchers.
- Explicit link to the original UUID: the REP must reference the fiscal folio of the income invoice it settles, and it cannot be stamped if that relationship is missing or incorrect.
Unlike a regular invoice, the CFDI that carries the payment complement is issued with its Total field at zero: the payment amount lives inside the complement's own node, not in the body of the voucher.
Required Fields on the Payment Complement
A properly built CFDI payment complement includes, at minimum:
- UsoCFDI "CP01": the code reserved exclusively for payment-receipt vouchers, regardless of the use registered on the original invoice.
- Payment date: the actual date the money was received, not the date the REP is stamped (which is almost always later).
- Payment method: wire transfer, check, cash, or another method, using the corresponding SAT catalog key.
- Payment amount and currency: it must match what was actually collected, respecting the exchange rate when the invoice is in a foreign currency.
- Related document: UUID, folio, currency, and outstanding balance of the income invoice being paid.
- Recipient data: name, RFC (tax ID), and tax regime must match SAT's records exactly, just like on any CFDI 4.0.
Common Mistakes When Issuing the Payment Complement
The most frequent errors that trigger rejections or mismatches are:
- Stamping the REP after the five-calendar-day window, usually because the collections team doesn't notify billing on the same day a payment comes in.
- Mixing up PUE and PPD on the original invoice, which later forces a cancellation and reissue before the complement can be filed correctly.
- Totals that don't reconcile between the "Totales" node and the individual payments, especially with early-payment discounts or exchange-rate adjustments.
- Linking the wrong UUID, which is common when a customer has several open invoices and the payment gets applied to the wrong one.
- Leaving the outstanding balance unchanged, which makes an invoice look unpaid even after it has actually been settled.
Automating Payment Complement Issuance
For businesses with meaningful credit-sale volume, manually tracking the five-calendar-day deadline is hard to sustain month after month — it requires syncing collections, accounting, and billing within a very tight window. The alternative is integrating the collections system with a PAC (SAT-authorized certification provider) so that, the moment a payment is recorded, the CFDI payment complement is generated and stamped automatically, without depending on someone remembering to do it before the cutoff.
That same automation also cuts down on data-entry errors: the amount, payment date, and related UUID are pulled directly from the collections system instead of typed by hand, which removes most of the mismatches that trigger SAT compliance notices today. If your business is already dealing with this under CFDI 4.0, it's worth reviewing what CFDI 4.0 changed around recipient-data validation, since the same rules apply to the payment complement.
Frequently Asked Questions
What is the payment complement in simple terms?
It's the CFDI that documents a payment received after the original invoice was already issued, recording the date, amount, and payment method without altering the income voucher itself.
When is the payment complement issued?
It's issued every time a payment comes in for an invoice with the PPD payment method, and SAT requires it to be stamped no later than the fifth calendar day of the month following the month the payment was received.
Are the payment complement and the REP the same thing?
Yes. REP is the short name for "Recibo Electrónico de Pago," the everyday term for the payment complement; both refer to the same type "P" CFDI.
What happens if I don't issue the payment complement on time?
The voucher can be treated as late, which exposes the issuer to SAT compliance notices and can make it harder for the recipient to deduct the expense if the delay becomes recurring.
Does every invoice need a payment complement?
No. Only invoices with the PPD payment method require one; PUE invoices, where payment happens at the moment of billing, don't create the obligation to issue a REP.
If your business is still issuing payment complements by hand and the five-calendar-day deadline keeps slipping, at AISDC we connect your collections system to your PAC so the payment CFDI is generated and stamped automatically the moment each payment is recorded. Learn more about our CFDI invoicing services.