What is KSeF: how Poland’s e-invoicing system works
Choose who the buyer is and how the invoice was issued. The tool shows the route the invoice takes to them and from when it counts as received.
The buyer gets the invoice
In KSeF
The invoice counts as received on the day its KSeF number is assigned, not when an email or printout arrives (Art. 106na(3)).
| QR codes | only when the invoice is used outside KSeF |
| Extra Podmiot3 section | no |
| Access without logging in | via the QR code, or number, buyer tax ID and amount |
Basis: Arts. 106gb and 106na of the VAT Act; section 7 of regulation 2025 item 1815.
Prepared by Radif Partners · Method · VAT Act, regulations and ministry notices checked on 25 October 2026
KSeF, the Krajowy System e-Faktur or National e-Invoicing System, is the Polish Finance Ministry's platform through which invoices between businesses in Poland now pass. The seller no longer sends an invoice straight to the buyer: it sends an XML file in the FA (3) structure to the system, which checks it, assigns a KSeF number and makes it available to the buyer. A buyer with a Polish tax ID downloads the invoice from KSeF, directly or through its software or accountant. Under Article 106na(3) of the VAT Act the invoice is received on the day the KSeF number is assigned, so an email with a PDF no longer has legal effect. Consumers and foreign businesses get the invoice from the system in an agreed way, with a QR code. Since 1 February 2026 the system has been compulsory for receiving for every business, and for issuing from February or April 2026. Invoices are kept in KSeF for 10 years, and access comes through a login with permissions or the QR code on a visualisation.
An invoice’s route through the system
- Issue. The seller creates an FA (3) file in its software or the ministry’s tool and sends it to KSeF.
- Validation. The system checks the schema and the issuer’s permissions. A file with errors is rejected.
- Number and confirmation. An accepted invoice gets a 35-character KSeF number and the issuer an official receipt confirmation, described on the page on confirmation.
- Receipt. A buyer with a Polish tax ID downloads the invoice from the system. The day the number is assigned is the day of receipt under Article 106na(3) of the VAT Act.
How the number is built is covered on the KSeF number page, and the file structure on the FA(3) e-invoice page.
When the buyer does not collect the invoice in KSeF
Consumers, businesses not established in Poland and a few other groups in Article 106gb(4) do not download invoices from the system. The seller issues the invoice in KSeF but hands it over in an agreed way: by email, on paper, in a customer portal. The visualisation must carry a QR code that lets anyone check the invoice without logging in. How many codes are needed depends on the issuing mode:
QR codes on the invoice
QR codes on the invoice
1
| Label under code I | KSeF number |
| Code standard | ISO/IEC 18004:2024 |
What KSeF changes in daily work
| Before KSeF | With KSeF |
|---|---|
| invoice by email or post | invoice in the system, downloaded by the buyer |
| day of receipt: day of the email | day of receipt: day the number is assigned |
| duplicate on the buyer’s request | invoice available in the system for 10 years |
| correction note from the buyer | correction only by the issuer’s corrective invoice |
| any PDF layout | one FA (3) structure |
The ministry publishes a general description on its general information page, and the definition of a structured invoice on the page on the FA structure. Who the duty covers and from when is set out under the scope of the obligation and in the calendar.
What KSeF does for a business, and what it does not
The system makes several things easier: an invoice no longer gets lost in an inbox, there is no need to ask for duplicates, and the accounts team can download purchase invoices automatically. The tax office sees the same data, so some audit questions fall away. KSeF is not accounting software, though: it does not match payments, keep VAT records or remind you of deadlines. Nor does it check whether an invoice is correct in substance, for example whether the right rate was used; it checks only that the file follows the schema and that the issuer has the permission.
For a small business the key change is simple: purchase invoices must be downloaded from the system regularly, because they no longer arrive by email in a form that has legal effect. It is worth setting a fixed routine, such as downloading once a week, and giving your accountant access.