28/5/2026
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The National e-Invoicing System (KSeF) is one of the largest tax digitalization projects in Poland. As early as 2026, most entrepreneurs will be required to send Structured Invoices to the Ministry of Finance's system, and from 2027, the regulations will also cover the smallest taxpayers. Although the change may seem purely technical, it actually impacts work organization in companies, accounting processes, document flow, and owners' responsibilities.
28/5/2026
KSeF is a platform used for issuing, receiving, and storing structured invoices in XML format. After an invoice is sent to the Ministry of Finance's system, the document undergoes automatic validation, receives a unique KSeF ID number, and is archived in a central database for up to 10 years.
Implementation schedule - who and when will be obliged to use KSeF?
The legislator has foreseen three stages for the obligation to come into effect:
- from February 1, 2026 - the largest entities whose sales value, including VAT, exceeded PLN 200 million in 2025,
- from April 1, 2026 - other entrepreneurs (excluding the smallest ones),
- from January 1, 2027 - the so-called smallest taxpayers, i.e., entrepreneurs with monthly sales up to PLN 10,000 gross.
Grace period: A grace period is in effect until December 31, 2026, during which the Ministry of Finance will not impose penalties for technical errors in issuing invoices. However, for substantive errors (e.g., incorrect VAT amounts), taxpayer liability remains.
It is worth emphasizing, however, that even if you are not among the largest entities, it is crucial to have access to KSeF as early as February 1, 2026. This is because large companies – for example, the largest gas station chains – will be required to issue their invoices exclusively through KSeF from that date. This means that as an entrepreneur, you will need to download purchase invoices directly from the system to be able to account for them. A lack of access to KSeF can therefore genuinely hinder the daily operations of your company, even if the KSeF obligation itself only applies to you in later stages.
Will all invoices be in KSeF?
No. Although the system will cover most B2B economic transactions, the legislator has provided a catalog of exclusions. Mandatory invoices will include, among others:
- invoices in B2B relations,
- invoices for public institutions,
- advance and corrective invoices.
Exempt from this requirement are, for example:
- B2C invoices - invoices for consumers (individuals not conducting business activity) can be issued traditionally (paper or electronically) and are not subject to the KSeF obligation,
- fiscal receipts with a VAT ID up to PLN 450 - can serve as simplified invoices and are exempt from the KSeF obligation until December 31, 2026. From January 1, 2027, all invoices - including simplified ones - will have to be issued in KSeF,
- B2B invoices issued by entities whose total value of sales subject to mandatory KSeF does not exceed PLN 10,000 gross per month can be issued outside KSeF until December 31, 2026, or until the first time the limit is exceeded. The invoice that causes the limit to be exceeded, as well as all subsequent ones, must already be issued in KSeF – regardless of the start of the next month,
- VAT RR invoices - issuing them in KSeF will be optional from February 1, 2026, and depends on the decision of the flat-rate farmer,
- invoices issued by foreign entities,
- selected cases of VAT-exempt taxpayers.
Does KSeF apply to VAT-exempt entrepreneurs?
Yes, though with exceptions. Taxpayers benefiting from subjective or objective exemption also have an obligation to issue invoices in KSeF for transactions that require documentation with a structured invoice. VAT exemption does not mean exemption from the KSeF obligation.
How to issue invoices in KSeF?
To issue documents in the system, an entrepreneur should:
Tokens generated in the old KSeF 1.0 version will not work in the target KSeF 2.0 version. If you have old tokens, you should generate new ones in the MCU.
Once integrated, the process is standard – the invoice is created in the software, and the system automatically sends the XML file to KSeF. After successful validation, a KSeF ID (a unique invoice number in the system) and UPO (Official Receipt Confirmation) are assigned, which is a document confirming that KSeF has accepted the invoice and that it has been correctly registered in the system.
Offline mode – a solution for failures
In case of no internet access or system unavailability, the entrepreneur can use offline mode24. The condition is to have a current invoice issuer certificate.
An offline invoice contains two QR codes – one enabling invoice verification in KSeF and the other confirming the authenticity and integrity of the document.
An offline invoice must be sent to KSeF no later than the next business day after its issuance.
If the Ministry of Finance (MF) announces a KSeF failure via a message on the BIP website, the entrepreneur can issue an invoice in emergency mode – then, after the failure ends, they have 7 days to send the invoice to KSeF to assign it a number and ensure the document's formal validity.
In the event of a so-called total failure, meaning both KSeF and the BIP website, announced in mass media, invoices can be issued outside the system, and after the failure ends, there is no obligation to send them to KSeF.
How to prepare for KSeF?
The introduction of KSeF requires not only technical but also organizational changes. What steps should you take as an entrepreneur:
KSeF is not just a technological change, but a complete overhaul of the entire invoicing system in Poland. Proper preparation will allow you to seize the opportunity to streamline processes, automate accounting, and eliminate errors. However, this requires commitment and planning. The sooner your company starts working with KSeF, the easier it will adapt to the mandatory system in 2026.