Since when has KSeF been mandatory in Poland?

Poland's National e-Invoicing System (KSeF) became mandatory on 1 February 2026, following several postponements due to technical challenges. The obligation was introduced in stages:

• 1 February 2026: For businesses whose sales, including VAT, exceeded PLN 200 million in 2024.
• 1 April 2026: For most remaining businesses.
• 1 January 2027: For the smallest businesses benefiting from the temporary exemption for invoiced monthly sales of up to PLN 10,000 (including VAT).

The phased rollout marks an important milestone in Poland's transition to mandatory structured e-Invoicing.

The National e-Invoice System (KSeF) will not yet be imposed on taxpayers this year. The Ministry of Finance, after carrying out preliminary analyses, has identified flaws in the system concerning, among other things: code, handling and performance. In response to these problems, the Minister of Finance, Andrzej Domański, decided to audit the system and postpone the mandatory use of KSeF.

KSeF - messages to send, receive and view electronic invoices - was due to become mandatory for active VAT taxpayers from the beginning of July 2024, and for other entities from January 2025. Now, following the detection of errors, the new deadline for the mandatory implementation of KSeF has been postponed, probably to Q2 2025.

Consequences of postponing the KSeF

Postponement has its advantages, such as the possibility to better secure the system and to ensure better system performance. There is a concern that entrepreneurs may see the postponement of the KSeF implementation date as a signal that work on the system is slowing down internally.  This, in turn, may in the future cause serious problems in effectively and timely entering into the obligation to issue, send and store e-invoices in KSeF.

From a legal point of view, a law is required for the deferral, but the Minister's decision makes it only a matter of time. It is worth noting that the approval for the implementation of KSeF required a decision from the European Commission. By the decision of the EU Council, the mandatory use of the National e-Invoice System and structured invoices is possible in Poland from 1 January 2024 to 31 December 2026.

Consultation on KSeF completed

The Ministry of Finance has completed its work as part of the ‘We consult KSeF’ project. A total of approximately 10,000 people (stationary at the Ministry's headquarters and online) participated in 9 meetings, which lasted from 16 February to 1 March this year. The Ministry of Finance is currently analysing the comments made by the participants of the consultation. On the MF side, the work is very intensive, as the Ministry wants to present the draft legislative solutions already in the second half of March.

It is possible that vendors will be able to voluntarily invoice in KSeF for consumers (B2C) as well. However, the technical parameters will not change.

Following the consultations and technical review, the Ministry of Finance confirmed a phased implementation schedule. Mandatory e-Invoicing through KSeF came into effect on 1 February 2026 for large businesses and was extended to most other businesses on 1 April 2026.

It is worth noting that the first outcome of the consultation is the launch of a working group on the dispatch of a large number of e-invoices.