Poland: National e-Invoice System (KSeF) - new obligations for entrepreneurs

What is KSeF?

KSeF is a central ICT platform administered by the Ministry of Finance, used to issue, receive, and archive invoices in a structured form. A structured invoice is an electronic document in XML format, compliant with the applicable FA(3) logical schema. The moment of issuing an invoice is considered to be its effective transmission to KSeF and the assignment of a unique identification number.

The legislator has planned to introduce KSeF in stages:

• from 1 February 2026 – the obligation applies to taxpayers whose gross sales in 2024 exceeded PLN 200 million;
• from 1 April 2026 – the obligation is extended to other VAT taxpayers with their registered office or permanent place of business in Poland;
• from 1 January 2027 – the smallest entities meeting the statutory low sales thresholds, whose total gross sales in a given month do not exceed PLN 10,000;
• in B2C relations, the use of KSeF remains voluntary.

Practical implications for businesses

The introduction of mandatory e-invoicing via KSeF entails significant changes in the day-to-day operations of businesses. In practice, this means that financial and accounting systems and IT tools must be adapted to handle structured invoices, and existing sales and purchasing processes and document archiving rules must be redesigned. The new invoicing model assumes that once an invoice is issued in KSeF, it is automatically made available to the contractor in the system, which affects the way documents are circulated and may promote further automation of accounting. At the same time, entrepreneurs must implement appropriate rules for granting and controlling access rights to KSeF to ensure data security and the proper performance of duties by persons involved in the invoicing process.

Sanctions

The legislator has provided for severe financial consequences for failure to comply with KSeF obligations, but the mechanism for applying them has been deliberately postponed. The year 2026 serves as a transition period – although the obligation to issue invoices in KSeF is already in force, the tax authorities will not impose administrative fines for non-compliance during this period. Only from January 1, 2027, will it be possible to apply sanctions which, depending on the nature of the violation, may reach an amount corresponding to as much as 100% of the VAT shown on an invoice issued outside KSeF, and in the case of documents without VAT shown, 18.7% of their value.

Summary

The National e-Invoice System introduces a significant change in the way VAT transactions are documented in Poland and requires businesses to adapt both their IT systems and internal accounting processes. Although the obligation to use KSeF will come into force in stages starting in 2026, the legislator has provided for a transition period without sanctions, which should be used to safely prepare organizations for the new reality. Proper planning of KSeF implementation will not only reduce tax risks from 2027, but also streamline document flow and VAT settlements.

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