Overview
Podmiot1 is the seller (in Polish, "sprzedawca" or "podmiot"). It is a required section of the FA(3) XML and identifies the party that issues the invoice. It carries the seller's tax identifier, name and address.
The seller's NIP is the most important field inside Podmiot1. In the Notaly sandbox the seller must be 2745013933, which is the NIP bound to the test certificate; sending 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 each account connects its own KSeF token and the seller NIP must match that account.
What Podmiot1 contains
Podmiot1 is built from two main groups. The first is DaneIdentyfikacyjne, which holds the NIP and the legal name (Nazwa). The second is Adres, which holds the country code (KodKraju, for example PL) and the address line (AdresL1), with an optional second line for more detail. Keep the name exactly as it appears in your registration documents; the tax office uses it together with the NIP to identify you.
The structure is the same for both the seller and the buyer. What changes between Podmiot1 and Podmiot2 is the role: Podmiot1 is the issuer, Podmiot2 is the recipient. If you integrate from an invoicing or ERP system, map your "issuer" object to Podmiot1 and your "customer" object to Podmiot2.
Why accuracy matters
A wrong NIP in Podmiot1 causes the KSeF system to reject the submission outright. A wrong or informal name is less critical for validation but looks careless to the buyer, because the name appears in the PDF and in the verification page. The address is used for identification and archiving, so keep it complete rather than abbreviated.
A complete, valid FA(3) example appears below. Copy it, change the buyer to your own test data, keep the seller NIP at 2745013933 while in the sandbox, and submit it through the Notaly API.
<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