What is Verifactu?

Verifactu (officially 'Sistemas Informaticos de Facturacion' or SIF) is Spain's new electronic invoicing system mandated by the Anti-Fraud Law (Ley 11/2021). It requires all invoicing software to:

1) Generate a unique hash (fingerprint) for each invoice, chained to the previous invoice's hash. This makes it impossible to modify or delete invoices without breaking the chain.

2) Include a QR code on every invoice that links to AEAT's verification service, allowing anyone to verify the invoice's authenticity.

3) Submit invoice records to AEAT either in real-time or within a defined timeframe.

4) Maintain an unalterable audit trail of all invoicing events.

Verifactu becomes mandatory for all businesses and autonomos in Spain starting July 2027. Since July 2025, it is already illegal to sell or use non-compliant invoicing software.

k-factu uses the built-in Verifactu engine to handle all Verifactu requirements: hash chaining, QR code generation, and AEAT submission.