Mexico CFDI E-Invoicing and Complemento de Pago

The problem

In Mexico an invoice is not a document you print — it is an XML that must be stamped by an authorised PAC before it legally exists. If the stamp fails, you have shipped goods you cannot bill. If the receptor's Uso CFDI, Régimen Fiscal or postal code does not match what the SAT holds for that RFC, the stamp is rejected outright. And since CFDI 4.0, the tolerance for mismatched receptor data is effectively zero.

The complexity does not stop at the invoice. Any invoice settled after issue in PPD terms requires a complemento de pago — a separate stamped document per payment, referencing every invoice it settles, with running balances that must reconcile exactly. Cancellation is no longer unilateral: a cancellation request goes to the SAT, the receptor may accept or reject it, and a rejected request leaves an invoice legally alive in your accounting whether you like it or not.

A standard SAP Business One installation knows none of this. There is no CFDI object, no PAC connection, no UUID to store, no place for the receptor's fiscal regime, and no mechanism to hold an invoice in a pending-cancellation state while the SAT decides. Teams typically end up running a separate stamping portal alongside B1 and re-keying — which means the ERP and the SAT diverge within a week.

What ECOSIRE builds

We build a dedicated CFDI add-on for your SAP Business One tenant, developed against the Service Layer and DI API, with fiscal data held in UDFs on Business Partners and marketing documents, catalogue data in UDTs, and CFDI documents themselves modelled as UDOs so they carry authorisations, an audit trail and a proper form in the B1 client.

CFDI 4.0 generation and stamping

On posting an A/R Invoice, the add-on assembles the CFDI 4.0 XML from the document, the Business Partner fiscal master data and the item-level SAT catalogue mapping, then submits it to your contracted PAC for timbrado. The returned UUID, the Timbre Fiscal Digital, the certificate serial and the stamp timestamp are written back to UDFs on the invoice and to the CFDI UDO, so the stamped identity of the document lives in the ERP rather than in a portal.

The same generation path covers A/R Credit Memos as Egreso CFDIs and, where in scope, transfer documents as Traslado with the Complemento Carta Porte — that complemento is priced separately at scoping because its data requirements are substantial.

SAT catalogue mapping

CFDI validity depends on catalogue codes that have nothing to do with your commercial data: ClaveProdServ and ClaveUnidad per item, FormaPago and MetodoPago per document, UsoCFDI and RegimenFiscal per receptor, ObjetoImp per line. We deliver these as UDF-driven mappings with a maintenance screen and defaulting rules — set at item group and Business Partner group level, overridable per record — so your users are not typing SAT codes into every line.

Complemento de Pago

When an Incoming Payment settles one or more PPD invoices, the add-on generates the Complemento de Pago (REP), stamps it through the PAC, and stores the resulting UUID against the payment. Each related-document block carries the prior balance, the amount paid and the remaining balance, plus the payment's own currency and exchange rate where the invoice and payment differ. Partial payments across multiple invoices are handled in one complemento, matching how B1 actually applies payments.

Cancellation workflow

Cancellation is modelled as a state machine, not a button. The add-on submits the cancellation request with the required motivo code and, where the motive demands it, the substituting UUID. It then polls the SAT acceptance status and reflects it back into B1: accepted, rejected, or in-process pending receptor response. An invoice with a rejected cancellation stays visible as such, so nobody assumes it disappeared.

Storage and delivery

Stamped XML and its PDF representation are archived against the document and can be emailed to the receptor on stamping. The PDF layout is produced as a Crystal Report carrying the mandatory elements — the CFDI QR code, the SAT and issuer digital seals, the UUID and the certification data — so it prints from the standard B1 preview and print flows rather than from a separate tool.

Controls

Every PAC exchange is logged with request, response, and outcome. Stamping failures are held in an exception queue with the PAC's rejection reason surfaced in plain terms, because 'CFDI40102' means nothing to an AR clerk. Where your process requires it, cancellation requests route through B1 approval procedures before submission.

Who this is for

Any business invoicing in Mexico from SAP Business One: local subsidiaries of foreign groups whose parent standardised on B1, Mexican distributors and manufacturers, and service companies whose PPD terms make complementos de pago a monthly grind. It is equally for the group that already stamps through a portal and is tired of the reconciliation gap between the portal and the ERP.

How delivery works

1. Scoping call. We review your PAC contract and its API, your document types, your PUE versus PPD mix, whether Carta Porte is in scope, your tax profile including IVA retentions and IEPS if applicable, and the state of your Business Partner fiscal master data — which is usually where the real work is.

2. Fixed quote. A written scope and a fixed price before development starts. Carta Porte, multi-branch Lugar de Expedición handling and unusual retention treatments are priced explicitly.

3. Build. Developed against your SAP Business One version, database platform and your specific PAC's API. Nothing is pre-built; typical lead time is one working week from signed scope.

4. Install into test. Installed into your test company database and stamped against your PAC's test environment, running your real document types end to end — invoice, payment complement, cancellation accept, cancellation reject — with your accounting team present.

5. Install into production. After sign-off, installed into production with your live PAC credentials and certificates, and the first live stamps run alongside your team.

6. Support. A defined support window for defect correction and configuration adjustment, on the terms stated in your quote. CFDI rules change; ongoing maintenance is a support arrangement, not an assumption.