Poland is consistently pushing ahead with the digitization of invoicing processes. With the “Krajowy System e-Faktur” (KSeF), a national eInvoicing system is now available and will be introduced on a mandatory basis. In April 2025, the Polish Ministry of Finance published an updated schedule with numerous adjustments affecting both technological and organizational aspects. This gives companies and software providers planning security at an early stage.
As previously announced, the introduction will be staggered, but with one key difference: the turnover for 2024 will now be used to determine which companies are affected and when. This gives those affected additional lead time.
Specifically, the following applies to electronic invoicing:
- From February 1, 2026: Mandatory for companies with gross annual sales of more than PLN 200 million in 2024.
- From April 1, 2026: Mandatory for all other companies.
This phased introduction will enable fair and realistic implementation, particularly for smaller market participants who need more time for technical integration.
Uniform deadline for additional obligations
In addition to the central invoice data exchange via KSeF, the Ministry of Finance has provided for further accompanying obligations. Originally, their introduction was spread over several dates – now a uniform deadline has been set: December 31, 2026. From this date, the following requirements will apply:
Obligation to include the KSeF number in bank transfers.
- Integration of cash register receipts with NIP information as electronic invoices.
- Obligation to include small-amount invoices in the system.
- Introduction of fines for non-use of KSeF.
- This bundled deadline reduces complexity and makes the transition more predictable for all parties involved.
Offline mode: KSeF becomes fail-safe
A key concern of the business community has also been addressed: the introduction of a new “Offline 24” mode. This allows companies to temporarily create electronic invoices outside the system in the event of technical malfunctions or a lack of internet connection – with a QR code and time stamp – and subsequently feed them into KSeF within one working day. This procedure is intended in particular for stationary sales, foreign business partners without a Polish tax number, or emergency situations. It increases reliability and gives companies additional flexibility in processing.
Technical preparations from mid-2025
The ministry is providing the technical requirements at an early stage to ensure a smooth transition:
- June 2025: Publication of the final API documentation for KSeF 2.0.
- September 2025: Opening of the test environment for software providers.
- November 2025: Release of the test version of the official app (“Aplikacja Podatnika”).
- February 1, 2026: Productive start for phase 1.
In addition, companies will be able to prepare their certificates for legally compliant signing from November 2025 – an important measure for continuous and secure invoicing processes.
More functionality: attachments and QR codes
Another technical improvement concerns complex invoice types such as media or telecommunications bills: From 2026, structured attachments can be submitted directly with the invoice in KSeF. Collective invoices, where individual items must be shown separately, can also be displayed in this way. In future, a declared attachment will be registered via the Polish e-citizen portal.
At the same time, the QR code will be standardized: in future, online and offline invoices will contain the same structured elements. This will make invoices easier to verify and simpler to compare with the original data in the system – especially when checking by customers or authorities.
