Overview
DaneIdentyfikacyjne is the identification block inside Podmiot1, the seller of a FA(3) invoice. It holds the seller's NIP and legal name (Nazwa), and it is required in every FA(3) invoice. The seller is always identified by a Polish NIP.
The two fields
NIP is the Polish tax identification number of the seller. In the XSD it must match the pattern of a valid NIP (10 digits with a valid check digit). In the Notaly sandbox the seller NIP must be 2745013933, the number bound to the test certificate; a different seller NIP returns a validation error before the invoice reaches KSeF and does not consume one of your three free test invoices. In production the seller NIP must match the account's own KSeF connection.
Nazwa is the seller's legal name, up to 512 characters. Use the exact name from your registration documents — the tax office matches it together with the NIP, and the name also appears in the PDF and on the official verification page.
Relationship to Podmiot2
The same identification structure appears in Podmiot2 for the buyer, but with more options. The buyer can be identified by NIP, by a foreign EU VAT number (KodUE plus NrVatUE), by a non-Polish tax identifier (KodKraju plus NrID), or by BrakID when the buyer has no tax identifier. The seller, in contrast, is always a Polish NIP holder.
Why accuracy matters
A wrong seller NIP causes an outright rejection by KSeF, because the NIP is part of how the system binds the invoice to the taxpayer account. A wrong or informal name passes validation but looks careless to the buyer, since it appears in the PDF and the verification page.
A complete, valid FA(3) example appears below with Podmiot1's DaneIdentyfikacyjne filled in.
<Faktura xmlns="http://crd.gov.pl/wzor/2025/06/25/13775/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Naglowek>
<KodFormularza kodSystemowy="FA (3)" wersjaSchemy="1-0E">FA</KodFormularza>
<WariantFormularza>3</WariantFormularza>
<DataWytworzeniaFa>2026-10-12T07:23:07Z</DataWytworzeniaFa>
<SystemInfo>einvoice-api</SystemInfo>
</Naglowek>
<Podmiot1>
<DaneIdentyfikacyjne><NIP>2745013933</NIP><Nazwa>Example Sp. z o.o. (FICTIONAL)</Nazwa></DaneIdentyfikacyjne>
<Adres><KodKraju>PL</KodKraju><AdresL1>ul. Testowa 1, 00-001 Warszawa</AdresL1></Adres>
</Podmiot1>
<Podmiot2>
<DaneIdentyfikacyjne><NIP>1234563218</NIP><Nazwa>Test Customer S.A. (FICTIONAL)</Nazwa></DaneIdentyfikacyjne>
<Adres><KodKraju>PL</KodKraju><AdresL1>ul. Probna 2, 30-001 Kraków</AdresL1></Adres>
<JST>2</JST>
<GV>2</GV>
</Podmiot2>
<Fa>
<KodWaluty>PLN</KodWaluty>
<P_1>2026-10-12</P_1>
<P_2>FV/2026/10/001</P_2>
<P_13_1>1000.00</P_13_1><P_14_1>230.00</P_14_1>
<P_13_2>301.00</P_13_2><P_14_2>24.08</P_14_2>
<P_15>1555.08</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>SaaS subscription - October</P_7>
<P_8A>pcs.</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>Support</P_7>
<P_8A>hrs.</P_8A>
<P_8B>2</P_8B>
<P_9A>150.50</P_9A>
<P_11>301.00</P_11>
<P_12>8</P_12>
</FaWiersz>
</Fa>
</Faktura>Sources
Source: crd.gov.pl