Self-Billing and Third-Party Invoicing Under VeriFactu: Who Issues, Who Is Liable

Self-Billing and Third-Party Invoicing Under VeriFactu: Who Issues, Who Is Liable

The party who sells is not always the party who invoices. Spanish invoicing rules have long allowed the invoice to be issued by the customer (self-billing, known locally as facturación por el destinatario) or by a third party (an accounting firm, a platform, an agricultural cooperative). With Spain's anti-fraud invoicing regulation now fully in force — companies since 1 January 2026, self-employed workers since 1 July 2026 — these arrangements remain perfectly legal. What has changed is that every invoice must produce a billing record inside a compliant SIF: SHA-256 chained hashes, a mandatory QR code, an event log and tamper-proof storage. That changes who does what.

When the customer or a third party issues the invoice

Self-billing makes sense whenever the customer has better data about the transaction than the supplier:

• Farmers whose cooperative settles deliveries and issues invoices on their behalf.
• Hauliers working for a large shipper that knows exactly which loads were carried and bills for them.
• Creators and freelancers paid through a platform that invoices the end clients or advertisers.

Third-party invoicing is the classic case of an accountant or an intermediary issuing invoices on the business owner's behalf.

The agreement: no paperwork, no delegation

Two conditions must be met before a customer can invoice in the supplier's name:

1. A prior agreement between the parties, documented. No specific form is required, but a written agreement with date, scope and duration is strongly advisable. 2. A defined procedure for the supplier to accept each invoice. Acceptance can be express or tacit, but the mechanism must be spelled out in the agreement.

For third-party invoicing a mandate is enough, but the third party always acts in the name and on behalf of the supplier, who remains the taxable person.

Which SIF generates the billing record?

This is the practical novelty. The billing record with its SHA-256 chained hash must be created at the moment the invoice is issued, in the system of whoever materially issues it:

• If the customer self-bills, the record is generated in the customer's SIF but attributed to the supplier, whose Spanish tax ID appears as issuer.
• If a third party invoices, the record is generated in the third party's SIF, again identifying the supplier as the invoice issuer.

If that system runs in VeriFactu mode, records are transmitted to the Spanish tax agency (AEAT) continuously as invoices are issued. In non-VeriFactu mode, records are kept locally, signed, with a full event log, ready to be handed over if the AEAT requests them. In both modes every invoice carries a verifiable QR code.

Dedicated series are mandatory here

Spanish invoicing rules require separate invoice series whenever invoices are issued by the customer or by a third party. A supplier whose cooperative bills part of their output will therefore run at least two series: their own, and the one used by the cooperative on their behalf. This fits the hash chain neatly — each series keeps its own sequence and traceability, and invoices generated in different systems never get mixed.

Delegating does not shift liability

The point most businesses miss: even when the customer or the accountant issues the invoice, the supplier remains the taxable person responsible. It is the supplier who answers for invoices being correctly issued, recorded in a compliant SIF and reflected in their VAT returns. The penalty for using non-compliant invoicing software can reach 50,000 euros per tax year (article 201 bis of the Spanish General Tax Law), and outsourcing the issuing does not transfer that exposure.

Self-billing agreements signed for the Spanish market should therefore now include:

• Confirmation that the issuer's SIF complies with Royal Decree 1007/2023 and which mode it operates in (VeriFactu or non-VeriFactu).
• Regular delivery of billing records or invoice copies back to the supplier, for bookkeeping and VAT.
• A protocol for errors: who issues the corrective invoice and in which series.

Quick checklist

• Written prior agreement with a defined acceptance procedure.
• Dedicated series for invoices issued by the customer or third party.
• Billing record generated in a compliant SIF, with the supplier's tax ID as issuer.
• Invoice copies and records flowing back to the supplier.
• Annual review of the agreement and of the transmission mode.

Done well, delegated invoicing removes admin from the party with the least back-office capacity. Done badly, it leaves a supplier legally liable for invoices they have never even seen.