Digitization of the tax system – what exactly is KSeF?

The National e-Invoice System (KSeF) is a platform developed by the Ministry of Finance that enables the issuance, transmission, and receipt of electronic invoices in a structured format. It is part of the digitization of the Polish tax system and represents a significant change in the way invoices are issued. Instead of sending documents in PDF or paper form, all invoices are sent to a single, central system. This makes it easier for the tax authorities to control and analyze data, and gives companies the opportunity to automate and simplify their accounting processes. KSeF has been operating on a voluntary basis since January 2022, but it will only become mandatory in 2026.

How KSeF works

KSeF enables the issuance of structured invoices in XML format using integrated financial and accounting software. The issuer receives an official confirmation of receipt (UPO). The recipient of the invoice gains access to it by authenticating themselves in KSeF or by providing specific data relating to the invoice (so-called anonymous access).

Mandatory introduction of KSeF by entrepreneurs

In accordance with the amendment to the Act, the introduction of the mandatory KSeF system has been divided into three stages depending on the size of the entrepreneur:

1) from February 1, 2026, for large taxpayers (with a sales value for 2024 exceeding PLN 200 million including tax);

2) from April 1, 2026, for other entrepreneurs, except for micro-entrepreneurs whose monthly sales do not exceed PLN 10,000 gross;

3) From January 1, 2027, also for micro-entrepreneurs whose monthly sales do not exceed PLN 10,000 gross.

Exemptions – will all paper invoices disappear from circulation?

It is worth noting that, according to the announcements of the Ministry of Finance, the obligation to issue invoices in the National e-Invoice System will ultimately apply to all entrepreneurs, regardless of their turnover.

At the same time, the legislator provides for certain exemptions from the obligation to use KSeF, which will be excluded:

1) consumer invoices (so-called B2C);

2) tickets that are considered invoices, including receipts on toll motorways,

3) invoices issued under OSS (One Stop Shop) and IOSS (Import One Stop Shop).

Amendments to the VAT Act

The amendment modifies, among others, Articles 106na and 106nb of the VAT Act and introduces a new catalog of sanctions related to non-compliance with the obligation to issue invoices via KSeF. Under the new provisions, invoices will only be considered issued once they have been sent to the system and an identification number has been obtained from KSeF. In practice, this means that it will be necessary to have infrastructure enabling communication with the Ministry of Finance’s system. Importantly, invoices issued outside KSeF will not be considered valid, which may lead to serious tax consequences, including denial of the right to deduct input tax or the application of administrative sanctions.

Tax consequences of using KSeF

In addition to obligations, the system also offers certain benefits, including from a tax perspective. Faster VAT refunds (up to 40 days) are provided for taxpayers using the system, as well as greater certainty of turnover thanks to a centralized invoice register. On the other hand, failure to comply with the new regulations may lead to the risk of accounting errors, bottlenecks in the invoicing process, and even administrative penalties.

Implementation – how to prepare for the obligation to use KSeF?

The implementation of KSeF should be preceded by an internal audit of document circulation processes, IT systems, and responsibility for the fulfillment of tax obligations. It is also crucial to properly regulate relations with contractors, in particular with regard to the moment of delivery of an invoice, which in the case of KSeF will depend on the date of making the document available in the system, and not, as has been the case to date, on the physical delivery of the document to the other party.

Summary

The adopted amendment to the VAT Act determines the mandatory implementation of the National e-Invoice System (KSeF) within precisely defined deadlines, starting from February 2026.

Although this change has the potential to simplify and digitize accounting processes, it also imposes a number of new obligations on businesses, both in terms of technical adaptation of systems and the introduction of internal procedures compliant with the regulations. It is worth bearing in mind that failure to prepare for the mandatory KSeF may result in serious tax consequences, including the loss of the right to deduct VAT or the imposition of administrative sanctions. Businesses should therefore start implementation activities now, including auditing their invoicing processes and updating their internal documentation and contracts with contractors.