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Chaining

In Veri*Factu there are no signatures in the records; instead, there is a hash and a chain.

The chain applies to all Veri*Factu records. Therefore, create, cancel, and correction operations must all be chained.

This chain is generated by SDH as records arrive, and it must NOT be chained based on invoice numbering.
The chain even spans across different invoice series.

The new VeriFactu regulation does not modify any previous billing regulation, which requires invoices to be issued correlatively*, without gaps.

Each Billing Software handles invoicing operations differently, so it is the software’s responsibility to comply with invoicing regulations.

For example:

Example 1 — Parallel invoice creation

A Billing Software, when issuing an invoice, first "reserves" an invoice number. If two processes are generating invoices simultaneously, one of them may finish earlier and send invoice 4 before invoice 3 to SDH.

This is allowed. There are no gaps in the invoicing sequence, and the chain would be:

2 → 4 → 3

If SDH returns an error for an invoice sent (e.g., invoice 3), that invoice remains in draft and the user should be able to continue editing it until it is correct.
The number cannot be deleted, because invoicing regulations do not allow gaps.

Example 2 — Batch invoicing with errors

A Billing Software processes delivery notes in a batch to create invoices 1, 2, 3, and 4. SDH accepts 1 and 2, but invoice 3 fails validation.
Typically, the Billing Software will not send invoice 4 until invoice 3 has been corrected.

Important: QR printing and acceptance

When printing an invoice, it must include the QR code provided by SDH after the invoice is accepted.
Therefore, if SDH does not accept the invoice, it cannot be handed to the customer.
The Billing Software must handle these scenarios appropriately.

Additional topics to consider

  • What to do if invoices cannot be issued with a QR?

  • Developer FAQs

    • Section 6-PROHIBICIÓN DE NUMERACIÓN DUPLICADA DE UN REGISTRO.
    • Section 10-IMPORTACIÓN DE FACTURAS DESDE OTRO SISTEMA.
    • Section 15-CHEQUEO AUTOMÁTICO DEL CORRECTO ENCADENAMIENTO. COMPROBACIONES AUTOMÁTICAS A REALIZAR POR LOS SIF.
    • Section 17-FORMA DE PROCEDER ANTE ERRORES COMETIDOS AL FACTURAR: RECTIFICACIONES, ANULACIONES, SUBSANACIONES.
    • ...