The delay was decided after the government identified critical issues in the original KSeF 1.0 platform. This was followed by extensive public consultations, which led to updated requirements for the B2B mandate and the development of the KSeF 2.0 central platform. The feedback from participants has been compiled into a comprehensive public FAQ shared publicly.
Invoice delivery and format
The 2026 Polish e-invoicing mandate will follow a Centralized Exchange model, similar to what was implemented in Italy, with a central platform called KSeF (Krajowy System e-Faktur) serving both invoice issuers and recipients. It is therefore not compliant with the upcoming ViDA directive, which may require further adaptations to be implemented in the future.
All B2B invoices between Polish taxpayers will need to be submitted through this KSeF central platform, primarily via API. For smaller companies, the tax authority provides free tools, including one allowing invoices to be entered manually. Once an invoice is validated, KSeF assigns it an official invoice number, which acts as a unique identifier.
Invoices must be issued in the FA(3) XML format, a local adaptation of the EN 16931 standard. While FA(3) follows the general EN 16931 data model and principles, it is not a CIUS and does not fully comply with the standard. Extracting data from FA(3) invoices for international use may require extra steps, but this is not expected to be overly complicated.
QR verification codes and Offline Mode
All B2B invoices must generally be sent electronically via KSeF. However, PDFs or paper copies are allowed in certain situations, such as cross-border transactions or when the KSeF platform is temporarily unavailable due to maintenance or outages. These non-electronic invoices must include a QR verification code that enables recipients to verify the invoice on KSeF.
Additionally, if real-time submission is not feasible, suppliers can rely on the “Offline Mode“. In this case, invoices can be sent in a non-electronic way (such as PDF or paper) but must in any case be submitted to KSeF within the next business day. Offline invoices include two QR codes: one to allow for invoice validity verification on KSeF, and the other to confirm the supplier’s identity.
B2B mandate implementation timeline
The rollout of mandatory B2B e-invoicing in Poland will be phased, based on company size and turnover:
- February 1, 2026: Large companies with annual turnover above PLN 200 million must comply.
- April 1, 2026: All other companies, excluding micro-businesses, must begin complying.
- January 1, 2027: Micro-businesses—defined as those issuing invoices under PLN 450 (~€106) and generating monthly sales below PLN 10,000 (~€2,364)—must comply.
A grace period extends until the end of 2026, during which no sanctions will be applied, giving companies additional time to fully adapt to the new system.
Additionally, the KSeF 2.0 platform will available for testing starting from September 30, 2025.
Possible use of KSeF for B2G transactions
Electronic invoicing is already in use in Poland for Business-to-Government transactions. Indeed, all public authorities must accept electronic invoices via the PEF (Platforma Elektronicznego Fakturowania) central platform in plain PEPPOL BIS 3.0 UBL format, although suppliers can still submit invoices in PDF or paper format if they choose.
However, from 2026, e-invoicing adoption for B2G transactions is expected to skyrocket, as all public administrations will also be accessible via the KSeF platform. This will allow companies to send invoices to both their private (B2B) and public (B2G) customers through a single platform, using the FA(3) format, greatly simplifying the process.
Stay updated and learn more about this country in our detailed Poland Country Profile.
