The National E-Invoice System is already commonplace for most taxpayers, but its final stage is still ahead. On September 16, 2026, the Ministry of Finance announced that it is working on an amendment to the VAT Act that will extend the end of the penalty-free period for errors in applying the National E-Invoice System to December 31, 2027. The announcement coincided with several changes that will impact invoicing from January 1, 2027.
Postponement of penalties is not a postponement of obligation
For issuing an invoice outside the National Tax and Finance Register (KSeF), despite the existing obligation, the head of the tax office can impose a fine of up to 100% of the tax indicated on the invoice, or up to 18.7% of the total amount due for a tax-free invoice. Penalties also apply for using exceptional procedures, preparing an invoice inconsistently with the template, and failing to submit it to the system on time. Under current regulations, these penalties would apply from January 1, 2027, but the ministry's proposal postpones this date by one year, to 2028.
The Ministry of Finance emphasizes that the postponement of sanctions does not mean exemption from the obligation. In 2027, the tax administration will primarily support entrepreneurs and remind them of their obligations, but will also respond to invoices issued outside the National Tax and Finance System (KSeF), unless they fall within the statutory exceptions, and will investigate whether non-compliance with the system leads to inaccurate tax settlements.
A financial penalty is just one of the possible consequences. A document issued outside the system where the KSeF is in force is not a structured invoice within the meaning of the Act. This may raise doubts on the part of the buyer regarding VAT deduction and increases the risk of objections during an audit, even if no financial penalty is imposed.
It's also important to remember that the announcement isn't yet law. The ministry is just beginning to draft the bill, and January 1, 2027, is just over three and a half months away. During that time, the change would need to pass through the government, the Sejm, and the Senate, and be signed by the President. The current date remains in effect until the amendment comes into force. Therefore, it's prudent to plan implementation as if penalties were to begin in January, and treat any delay as a safety margin.
End of transition periods on 1 January 2027.
The largest taxpayers entered the system on February 1, 2026, most others on April 1, while the smallest taxpayers, whose monthly sales documented by invoices do not exceed PLN 10,000 gross, will begin issuing invoices in the KSeF system on January 1, 2027. Until the end of 2026, they can issue paper or PDF invoices outside the system. In practice, this will include small-scale sole proprietorships and VAT-exempt taxpayers.
The second group that will be particularly affected by the change are entities selling through cash registers. Until December 31, 2026, Article 145n of the VAT Act allows for the issuance of invoices using cash registers and the treatment of receipts with the buyer's Tax Identification Number (NIP) up to PLN 450 gross or EUR 100 as simplified invoices. This transitional period expires on January 1, 2027, and the amended Article 111, paragraph 3a, point 1 means that cash registers are no longer used for issuing invoices, so receipts with NIPs are no longer considered simplified invoices. Sales to VAT payers recorded at the cash register, even if they do not exceed PLN 450, will have to be documented with a structured invoice in the National Sales and Services Register (KSeF). This applies to retail, restaurants, garages, gas stations, and services—in other words, wherever business customers request a NIP on the receipt. Here, you need to ensure the integration of the cash register or sales system with KSeF, because simply issuing a receipt will no longer be enough.
KSeF number in payment information
From 1 January 2027, payments between active VAT payers, including split payment transfers, will require the invoice's KSeF number, pursuant to Article 108g of the VAT Act. This will allow the tax administration to link a specific invoice to a specific transfer.
This requirement may seem cosmetic, but it affects the payment process, not just invoicing. The KSeF number must be available at the time of transfer, which for many companies means changing invoice approval procedures, integrating their accounting system with their banking system, or adapting mass payment files. It's worth testing this in the fourth quarter, not the first week of January.
Improvement package
After consultations with business organizations and tax advisors, the Ministry of Finance has prepared a package of seven improvements that are to come into force on January 1, 2027. These are primarily technical in nature, but some of them are also important for the organization of work within a company.
The Taxpayer application will enable the marking of invoices with statuses, such as "to be booked," "to be clarified," or "not to be booked," which will facilitate the organization of accounting documents. Tokens that were scheduled to expire at the end of 2026 will remain in use, and their validity can be set from one to 365 days, with the option of automatic renewal with the owner's consent. This is important for companies that have relied on tokens for their KSeF integration and were concerned about service interruptions.
Another new feature is the ability to extend invoices with business context, linking them to projects, cost categories, or operational events. This data will be stored in the KSeF itself, rather than in an XML file structure. The solution is intended to enhance analytical capabilities and also allow the tax authorities to better analyze financial flows.
The Ministry also announces higher limits for API queries, which is important mainly for entities processing hundreds of thousands of documents per month, and the ability to report suspicious invoices and fraud attempts directly via the API.
How to use extra time
If the postponement of fines is confirmed, 2027 will be a time to streamline processes, not postpone them. First, it's worth examining what sales documents are currently being created outside the main invoicing system, especially at cash registers, in online stores, and in industry-specific systems. Next, it's necessary to verify the authorizations of employees and accounting offices, as well as procedures in the event of a system failure. This also includes preparing payments with a KSeF number and reviewing contracts with contractors regarding invoice delivery methods and liability for errors. It's also good practice to document actions taken, as this will demonstrate due diligence in the event of an audit.
The changes to the National Securities and Exchange Commission (KSeF) therefore have two layers. The first is the announcement of a more lenient sanctions regime, which is still awaiting adoption. The second is the hard changes, effective January 1, 2027, which are not dependent on this amendment. Companies that prepare for both will enter the new year without stress, regardless of the bill's fate in parliament
This article is for informational purposes only and does not constitute legal advice.
The law is current as of September 18, 2026.
Author/Editor of the series:
