Structured e-Invoice – an electronic invoice in XML format compliant with the FA(2) schema. It contains a defined set of fields such as buyer data, seller data, line items, and amounts.
National e-Invoicing System (KSeF) – a government platform for issuing and receiving structured invoices, operating 24/7. Documents are stored there for 10 years.
Authentication – access to KSeF requires authorization using one of three tools: a qualified electronic signature, a trusted profile, or a qualified seal.
Archiving – documents are stored in KSeF for 10 years from the date of issue. The taxpayer is not required to store them locally.
QR Code – a unique visual identifier of a structured invoice issued in the KSeF system. It allows the recipient to scan the invoice and automatically verify its authenticity.
KSeF Offline – an emergency (offline) operating mode of the National e-Invoicing System (KSeF) used when the taxpayer cannot connect to KSeF but still needs to issue invoices.
KSeF Identifier – a unique number assigned to each e-invoice sent to and received by the National e-Invoicing System (KSeF) in Poland. It serves as proof that the invoice has been accepted by the system (confirmation of its “official issuance” under tax law).
Duplicate – in the KSeF system, each party can download the original document at any time. The traditional concept of a duplicate invoice no longer exists.
KSeF Certificate – a digital authentication key that enables users to issue and send e-invoices to KSeF, download and view invoices, and authorize users and permissions.
KSeF Token – a special access key (string of characters) generated for applications integrated with KSeF.
KSeF Permissions – a set of roles and access rights authorizing activities such as issuing, receiving, and viewing invoices.
KSeF API –a programming interface that allows accounting software to integrate with the KSeF system.
Invoice Visualization – the graphical form of an XML invoice (e.g., a PDF generated from KSeF).
Invoice Acceptance Date – the moment when KSeF confirms the acceptance of the invoice (the official issue date).
Invoice Status in KSeF – information about the document’s status (e.g., “accepted,” “rejected,” “under validation”).
