KSeF offline mode

KSeF offline mode defines how to issue an invoice when the national platform is unreachable, then regularise it later.

Definition

The offline mode (or emergency mode) of Poland's KSeF refers to the procedures that allow an invoice to be issued without immediate validation by the platform, when it is unavailable (outage, maintenance) or the issuer cannot connect to it.

It is a safety valve: invoicing activity should not stop simply because the central system is momentarily unreachable.

How it works

The principle is a deferred submission:

• the invoice is prepared offline in the expected structured format and handed to the buyer;
• once the platform is reachable again, the issuer submits it to KSeF for validation and to obtain its identifier;
• this regularisation must occur within a deadline set by the regulation.

Depending on the case, an offline invoice may carry security elements (for example a two-dimensional code) that let the buyer verify it while final registration is pending.

Good to know

Offline mode is meant to stay exceptional: it does not waive the final registration in KSeF, which remains mandatory for the invoice to obtain its definitive status and its Numer KSeF.

The exact activation conditions, later-submission deadlines and content of the security elements depend on Poland's official specifications, which have evolved during the rollout; always refer to the rules currently in force.