National e-Invoicing System for small and medium-sized enterprises – the first weeks of mandatory electronic invoicing

June 8, 2026

As of 1 April 2026, the mandatory National e-Invoicing System (Krajowy System e-Faktur) has been extended to another, significantly broader group of businesses – all active and VAT-exempt taxpayers, with the exception of the smallest entities whose monthly sales documented by invoices do not exceed PLN 10,000. For this latter group, the obligation to issue structured invoices will only come into force on 1 January 2027.

It should be recalled that, as of 1 February 2026, the National e-Invoicing System had already become mandatory for large enterprises whose sales value exceeded PLN 200 million in 2024. The next implementation phase, effective from 1 April 2026, covered small and medium-sized enterprises as well as sole proprietorships. Consequently, the National e-Invoicing System has become the standard invoicing method for the majority of Polish businesses.

Initial challenges and practical conclusions

The first weeks of mandatory use of the National e-Invoicing System by small and medium-sized enterprises revealed several important organisational and technical issues. The most frequently reported challenge was not the software itself, but rather a misunderstanding of roles and responsibilities. Some entrepreneurs expected accounting offices to assume full responsibility for operating the system, while the key authorisations related to logging in and granting access rights remain the responsibility of the business owner or management board.

Another important practical issue is that a structured invoice acquires legal validity at the moment it is submitted to the National e-Invoicing System, rather than at the moment of its actual issuance or the agreed invoice date. In practice, this requires businesses to adjust their internal processes, particularly with regard to the timely issuance of documents.

It is also worth noting that, in 2026, the legislator decided not to introduce immediate financial penalties for failure to implement the National e-Invoicing System. Some businesses interpreted this as a signal that preparations could be postponed. However, this approach has already resulted in genuine operational difficulties, including delays in cost settlements and problems with system integration.

The PLN 10,000 threshold – who is covered by the exemption?

The regulations provide that taxpayers whose monthly sales documented by invoices subject to the National e-Invoicing System do not exceed PLN 10,000 are not obliged to issue invoices through the system. In practice, doubts have arisen regarding the method of calculating this threshold, particularly whether the PLN 10,000 limit includes only invoices covered by the mandatory system, or also receipts up to PLN 450 recognised as simplified invoices, as well as invoices issued using cash registers.

The answer to these questions is of significant practical importance. Depending on the adopted interpretation, the total sales threshold allowing a taxpayer to benefit from the postponement may be considerably higher than PLN 10,000. This issue should therefore be closely monitored by affected businesses.

KSeF 2026: last chance to prepare your business

The National e-Invoicing System is becoming an integral element of value added tax settlements in Poland. For businesses covered by the obligation as of 1 April 2026, the key priorities are identifying the appropriate roles within the invoicing process, updating accounting systems, and training employees. Businesses that have not yet implemented the system should take the necessary steps as soon as possible, as the absence of penalties in 2026 does not mean the absence of a legal obligation.

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