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Open a Polish KSeF invoice

Open a Polish KSeF FA(3) invoice in your browser and read it as a clear document. Reading only: no check, conversion or submission to KSeF.

In short

See supported XRechnung, ZUGFeRD, Factur-X, Peppol, UBL and CII files as clear invoices, and save them as PDFs. Free, and the file stays on your device. Free.

You can read a Polish KSeF invoice in your browser with the Klarbon viewer: drop the FA(3) XML file and it appears as a readable document with seller, buyer, lines, VAT rates and the amount due. It is free, needs no account and the file never leaves your device. Opening is in beta and is reading only: Klarbon does not check, convert for submission or send anything to KSeF.

What is a KSeF invoice?

KSeF (Krajowy System e-Faktur) is Poland's national e-invoicing system, run by the Ministry of Finance. A structured invoice is an XML file in the official FA structure, issued through KSeF and given a KSeF number (Ministry of Finance, in Polish). From 1 February 2026, FA(3) replaced FA(2) for this invoice structure (Ministry of Finance, in Polish).

For taxpayers in scope, issuing through KSeF became mandatory on 1 February 2026 for businesses whose 2024 sales exceeded PLN 200 million including VAT, and on 1 April 2026 for the remaining taxpayers. Until 31 December 2026, invoices can still be issued outside KSeF when the monthly VAT-inclusive sales total on those invoices does not exceed PLN 10,000 (Ministry of Finance, in Polish). So if you buy from a Polish business, you will increasingly receive FA(3) files.

How do I open a KSeF invoice?

  1. Choose or drop the .xml file, for example one your Polish supplier sent you or one downloaded from KSeF.
  2. Klarbon recognises FA(3) from the file's content, whatever its name.
  3. Read the invoice: seller and buyer with their tax numbers, invoice number and date, each line, the VAT breakdown by rate, the amount due and payment details.
  4. Fields that exist only in FA(3), such as split payment (mechanizm podzielonej płatności), reverse charge or the margin scheme, appear in a separate section under their official Polish names.
  5. Print it or save it as a PDF if you want a readable copy.

A synthetic example: an FA(3) file from "Przykład Sp. z o.o." for PLN 1,230.00 opens as an invoice showing both parties' NIP numbers, two lines at 23% VAT, tax of PLN 230.00 and a note that split payment applies.

I am a foreign buyer. Do I need KSeF?

Not to read the invoice. A foreign buyer without a Polish tax number cannot log in to KSeF, so the Polish supplier issues the invoice in KSeF and passes it on in an agreed way, such as a PDF, by email or on paper, with a QR code that lets you confirm the invoice exists in KSeF (Ministry of Finance Q&A, in Polish). If your supplier also sends the XML file, the viewer lets you read it without Polish accounting software.

What will the viewer not show?

The KSeF number. KSeF assigns it when it accepts the invoice, and it is not part of the XML. For a buyer in KSeF, the invoice counts as received on the day the number is assigned (Ministry of Finance, in Polish).

The QR code. An invoice given to a buyer outside KSeF carries a QR code (Ministry of Finance Q&A, in Polish). Klarbon's readable copy has none, so it does not replace the supplier's visualisation.

Whether the invoice is valid. An FA(3) file that has not been through KSeF can display perfectly and still be rejected. KSeF decides that, not the viewer.

What Klarbon does not do with KSeF invoices

Klarbon does not log in to KSeF, does not download invoices from it, does not check FA(3) files against the Ministry of Finance's rules, does not convert them for submission and does not send anything to KSeF. A Polish business issues and receives its invoices through its invoicing software or the Ministry's own KSeF tools.

Is my file uploaded?

No. Open runs entirely in your browser, so the invoice stays on your device while you read, print or save it. Klarbon's other tools work differently: they send the file to Klarbon's servers and delete it after the request. See what happens to your files.

How do I save a KSeF invoice as a PDF?

Open the file and choose Print, then Save as PDF in your browser's print dialogue. You get a readable copy for your records, your bookkeeper or a payment approval. It is not a new invoice and not the supplier's QR visualisation: the invoice in KSeF remains the original. See print or save an invoice as a PDF.

What does it cost?

Nothing. Opening and saving a readable PDF are free and unlimited, with no account. Only tools that produce a new file cost a credit; see prices.

What next?

Frequently asked questions

How do I open a KSeF XML invoice?

Drop the file on the Klarbon KSeF viewer in any modern browser. It shows the invoice as a readable document with seller, buyer, lines, VAT and the amount due. It is free, needs no account and the file stays on your device.

I am outside Poland. Why did my Polish supplier send me a PDF and an XML file?

A Polish supplier issues the invoice in KSeF and passes it to a foreign buyer in an agreed way, such as a PDF by email, with a QR code that lets you confirm the invoice exists in KSeF. The XML is the structured invoice itself; the viewer lets you read it.

Does the viewer show the KSeF number and QR code?

No. KSeF assigns the number when it accepts the invoice, and the number is not inside the XML file, so the viewer cannot show it. Klarbon does not produce a QR code either.

Does opening a KSeF invoice check that it is valid?

No. Klarbon does not check FA(3) files against the Ministry of Finance's rules, does not convert them for submission and does not send anything to KSeF.

Are the labels in English?

The main invoice view is in your language. Fields that only exist in FA(3), such as split payment or margin scheme, are shown under their official Polish names from the FA(3) structure.

Sources

Updated 6 November 2026