A type of electronic invoice that is based on a unified XML document template and follows the FA_VAT logical structure. Issued and received through KSeF (Krajowy System e-Faktur) and using interface software, it represents the third type of invoice in Poland, followed by paper and other electronic invoices. KSeF assigns a unique identification number to each structured invoice, which validates and tracks it within the system. After issuance, the supplier informs the buyer using a process external to KSeF.