KSeF XML Validator

Validate your invoice XML against the FA(3) schema - free, no registration required

Send invoices to KSeF in the app See how the validator works

<?xml version="1.0" encoding="UTF-8"?>
<Faktura xmlns="http://crd.gov.pl/wzor/2025/06/25/13775/">
  <Naglowek>
    <KodFormularza kodSystemowy="FA (3)" wersjaSchemy="1-0E">FA</KodFormularza>
    <WariantFormularza>3</WariantFormularza>
    <DataWytworzeniaFa>2026-03-15T10:00:00</DataWytworzeniaFa>
    <SystemInfo>KSeFGPT</SystemInfo>
  </Naglowek>
  <Podmiot1>
    <DaneIdentyfikacyjne>
      <NIP>7018107174</NIP>
      <Nazwa>Firma Testowa Sp. z o.o.</Nazwa>
    </DaneIdentyfikacyjne>
    <Adres>
      <KodKraju>PL</KodKraju>
      <AdresL1>ul. Testowa 5</AdresL1>
      <AdresL2>00-001 Warszawa</AdresL2>
    </Adres>
  </Podmiot1>
  <Podmiot2>
    <DaneIdentyfikacyjne>
      <NIP>4832919201</NIP>
      <Nazwa>Kontrahent Test Sp. z o.o.</Nazwa>
    </DaneIdentyfikacyjne>
    <Adres>
      <KodKraju>PL</KodKraju>
      <AdresL1>ul. Odbiorcza 10</AdresL1>
      <AdresL2>31-100 Kraków</AdresL2>
    </Adres>
    <DaneKontaktowe>
      <Email>faktury@kontrahent-test.pl</Email>
      <Telefon>48123456789</Telefon>
    </DaneKontaktowe>
    <JST>2</JST>
    <GV>2</GV>
  </Podmiot2>
  <Fa>
    <KodWaluty>PLN</KodWaluty>
    <P_1>2026-03-15</P_1>
    <P_1M>Warszawa</P_1M>
    <P_2>FV/2026/03/001</P_2>
    <P_6>2026-03-14</P_6>
    <P_13_1>1500.00</P_13_1>
    <P_14_1>345.00</P_14_1>
    <P_15>1845.00</P_15>
    <Adnotacje>
      <P_16>2</P_16>
      <P_17>2</P_17>
      <P_18>2</P_18>
      <P_18A>2</P_18A>
      <Zwolnienie>
        <P_19N>1</P_19N>
      </Zwolnienie>
      <NoweSrodkiTransportu>
        <P_22N>1</P_22N>
      </NoweSrodkiTransportu>
      <P_23>2</P_23>
      <PMarzy>
        <P_PMarzyN>1</P_PMarzyN>
      </PMarzy>
    </Adnotacje>
    <RodzajFaktury>VAT</RodzajFaktury>
    <FaWiersz>
      <NrWierszaFa>1</NrWierszaFa>
      <P_7>Usługa konsultingowa</P_7>
      <P_8A>szt.</P_8A>
      <P_8B>1</P_8B>
      <P_9A>1000.00</P_9A>
      <P_11>1000.00</P_11>
      <P_12>23</P_12>
    </FaWiersz>
    <FaWiersz>
      <NrWierszaFa>2</NrWierszaFa>
      <P_7>Pakiet wdrożeniowy KSeFGPT</P_7>
      <P_8A>szt.</P_8A>
      <P_8B>2</P_8B>
      <P_9A>250.00</P_9A>
      <P_11>500.00</P_11>
      <P_12>23</P_12>
    </FaWiersz>
    <Platnosc>
      <TerminPlatnosci>
        <Termin>2026-03-29</Termin>
      </TerminPlatnosci>
      <FormaPlatnosci>6</FormaPlatnosci>
      <RachunekBankowy>
        <NrRB>12109010140000071219812874</NrRB>
        <NazwaBanku>Bank Testowy S.A.</NazwaBanku>
        <OpisRachunku>Rachunek firmowy PLN</OpisRachunku>
      </RachunekBankowy>
    </Platnosc>
  </Fa>
</Faktura>

Paste invoice XML and click "Validate XML"

Free, with a shared limit

Without registering, you can use the tools a total of 2 times within 24 hours. This limit is shared across all tools.

Check the data and amounts before using the result. The KSeFGPT app also lets you send invoices to KSeF after connecting your account to the system.

2 total uses within 24 hours
After creating an account: access to GUS data and manual editing of every invoice field
Full access to all platform modules

Create account

KSeF rejects an XML invoice: how to find the error

See how to use the free KSeFGPT validator to find an error in an XML file before sending it to KSeF.

This recording is in Polish.

Free Tools that humans LOVE to use

Share your thoughts - every review helps us make these tools better for you.

“Walidator wyłapał mi błąd w sumie P_15 na czterech fakturach z ERP, zanim je wysłałam do KSeF. Oszczędziłam dzień na korektach.”

Marta K. · Księgowa, biuro rachunkowe

“Najszybszy sposób na debug FA(3) – wklejam XML, widzę dokładnie który element nie trzyma schematu. Używam codziennie.”

Piotr W. · Dev / integrator

“Przed go-live KSeF przepuściliśmy cały hurt faktur testowych. Raport błędów jest czytelny nawet dla nietechnicznych osób w zespole.”

Anna S. · CFO, e-commerce

“Darmowe, bez rejestracji, działa w przeglądarce. Dokładnie tego potrzebowałem, żeby sprawdzić fakturę od nowego dostawcy.”

Tomasz L. · Właściciel, handel B2B

Free validator vs KSeFGPT Pro

	Free validator	KSeFGPT account
Checking FA(3) XML	Within the usage limit	Depends on the plan
Document history	No	Depends on the plan
Creating and sending invoices	No	Depends on the plan
Companies in one account	No	Depends on the plan
AI assistant for KSeF	Separate public chat	Depends on the plan
Invoice analytics	No	Depends on the plan
Support	Instructions and knowledge base	Depends on the plan

What is this KSeF XML?

This XML is a structured representation of an electronic invoice intended for submission or import to Poland's National e-Invoice System (KSeF).

XML describes an invoice in a machine-readable format. Instead of PDF or paper, the invoice is stored as data in a structure compliant with the XSD FA(3) schema.

KSeF does not accept invoices in PDF or Excel.

It only accepts structured XML data compliant with the schema.

This allows the system to automatically:

Verify VAT

Analyze data

Automate bookkeeping

Share invoices with contractors

Frequently asked questions

What is FA(3) XML and how does it differ from FA(2)?

FA(3) is the invoice structure used in KSeF since 1 February 2026. It replaced FA(2) and changed the scope and arrangement of some fields. Use the FA(3) documentation and schema when preparing new invoices.

How do I generate FA(3) XML from accounting software?

Check the invoice export option in your software's KSeF module. If it does not support FA(3), prepare the document in the generator or KSeFGPT app. Check the data and file before sending.

How do I open and preview FA(3) XML?

You can open XML in a text editor. Upload it to the validator to obtain a check result. Use the separate XML to PDF converter to prepare a readable invoice visualization.

How do I check XML before sending it to KSeF?

Paste the XML or upload a file and run the check. The tool reports detected structure and data issues, such as NIP, date or amount problems. Correct the reported errors. Validation does not replace KSeF's invoice acceptance status.

What errors can occur in FA(3) XML?

Common problems include malformed XML, missing required fields, incorrect date formats, invalid NIP numbers and inconsistent totals. The tool's messages indicate the scope of its checks; they do not assess the transaction's tax correctness.

Will the validator detect an invalid NIP?

The tool checks the NIP length and checksum, among other things. A mathematically valid result does not confirm that a company exists, its VAT status or whether the number belongs to the intended counterparty.

Why does P_15 differ by one grosz?

Rounding or different VAT calculation methods may cause this. Compare line-item amounts, totals by VAT rate and the total payable. For advances and corrections, account for the rules specific to that invoice type.

Can I convert a PDF to FA(3) XML?

Yes, using the separate PDF to XML converter. The validator works with XML. After conversion, compare the extracted data with the PDF and validate the prepared file.

Is XML validation a paid service?

The tool is free within a shared limit of 2 free-tool uses per 24 hours. A KSeFGPT account has separate features and limits defined by its plan.

Manage invoices in KSeFGPT

Connect your account to KSeF to send and receive invoices and use the history and features of your selected plan.

Create an account