---
name: ksef-invoice
description: >
Generates and checks KSeF FA(3) invoice XML for Polish e-invoicing: maps invoice data (PDF, text,
form fields) to the schema and picks P_12 rates, P_13_x totals, Adnotacje and buyer
identification. Covers domestic sales, reverse charge, WDT, export, VAT exemption, margin, OSS,
split payment, foreign currency, advance (ZAL) and settlement (ROZ) invoices, and explains
@ksefuj/validator errors. Use when issuing an e-invoice to KSeF, building FA(3) XML, or fixing
validation errors. To correct an invoice that was already issued, use ksef-correction.
---
# KSeF FA(3) Invoice Generation
Generate FA(3) invoice XML from the user's invoice data and check it with `@ksefuj/validator`. The
FA(3) schema uses `xs:sequence`, so element order matters everywhere. Corrective invoices are
summarized here; for step-by-step corrections of an issued invoice, use the ksef-correction skill.
Bundled references, loaded on demand:
- `references/vat-scenarios.md`: WDT, export, reverse charge, exemption, OSS, margin, split payment,
foreign currency
- `references/advance-invoices.md`: advance (ZAL) and settlement (ROZ) invoices
- `references/corrections.md`: corrective invoices (KOR, KOR_ZAL, KOR_ROZ)
---
## Schema and Resources
- Namespace: `http://crd.gov.pl/wzor/2025/06/25/13775/`
- XSD: `https://crd.gov.pl/wzor/2025/06/25/13775/schemat.xsd`
- KSeF 2.0 (production): https://ap.ksef.mf.gov.pl/
- KSeF 2.0 test environment (fake data, no legal effect): https://ap-test.ksef.mf.gov.pl/web/
- KSeF documentation portal: https://ksef.podatki.gov.pl/
There is no standalone XML validator in KSeF; the system validates only on submission, so check the
XML with `@ksefuj/validator` first.
---
## Validate Your Output
Validate the XML after generating it:
```bash
npx @ksefuj/validator invoice.xml
```
or from Node.js:
```js
import { validate } from "@ksefuj/validator";
const result = await validate(xmlString);
if (!result.valid) console.log(result.issues);
```
The validator runs three layers:
1. XSD validation against the official FA(3) schema.
2. Semantic rules from the Ministry of Finance information sheet (see
[Validator Issue Codes](#validator-issue-codes)).
3. Extra checks beyond what KSeF verifies: tax arithmetic, NBP exchange rates, bank account format.
---
## Top-Level XML Element Order
The schema uses `xs:sequence`, so element order is strictly enforced:
```
Faktura
└── Naglowek
└── Podmiot1 (seller, always identified by a Polish NIP)
└── Podmiot2 (buyer)
└── Podmiot3* (additional entity, optional)
└── PodmiotUpowazniony* (optional)
└── Fa
└── KodWaluty
└── P_1
└── P_1M*
└── P_2
└── WZ*
└── P_6* (single delivery/service date for all lines, only when different from P_1)
└── OkresFa* (billing period per art. 19a sec. 3/4/5 pt 4)
└── P_13_1..P_13_11 (only include fields relevant to this transaction, omit zeros)
└── P_14_1..P_14_5 (VAT amounts, only when P_13_x > 0)
└── P_15
└── KursWalutyZ* (only for advance invoices ZAL/KOR_ZAL, per art. 106b sec. 1 pt 4)
└── Adnotacje
└── RodzajFaktury
└── ... (corrective/advance-specific elements, see references/)
└── FaWiersz* (line items, optional for advance invoices)
└── Platnosc*
└── WarunkiTransakcji*
```
`KursWalutyZ` at `Fa` level is only for advance invoices (ZAL/KOR_ZAL). On regular
foreign-currency invoices the exchange rate goes in `FaWiersz/KursWaluty`.
---
## Invoice Scenarios
### Scenario 1: Domestic Sale at 23% VAT
Most common case. Buyer is a Polish company (has NIP).
Key fields:
- `P_13_1` = net amount at 23% | `P_14_1` = VAT amount | `P_15` = gross total
- `FaWiersz/P_12 = "23"` | `Adnotacje/P_18 = 2` (no reverse charge)
```xml
FA
3
2026-03-01T10:00:00Z
1234563218
Seller Sp. z o.o.
PL
ul. Przykładowa 1
00-001 Warszawa
9876543210
Buyer Sp. z o.o.
PL
ul. Kupiecka 5
30-002 Kraków
2
2
PLN
2026-03-01
FV/001/03/2026
1000.00
230.00
1230.00
2
2
2
2
1
1
2
1
VAT
1
Consulting services
h
10
100.00
1000.00
23
2026-03-15
6
```
---
### Scenario 2: Domestic Reverse Charge (Odwrotne obciążenie)
Used when the buyer is the VAT payer (art. 145e of the VAT Act, domestic reverse charge).
Key fields:
- `P_13_10` = net amount | no `P_14_x` (no VAT charged) | `P_15` = equals `P_13_10`
- `FaWiersz/P_12 = "oo"` | `Adnotacje/P_18 = 1`
- Optionally `FaWiersz/P_12_Zal_15 = "1"` if goods from Annex 15
```xml
FA
3
2026-03-01T10:00:00Z
1234563218
Seller Sp. z o.o.
PL
ul. Stalowa 10
00-001 Warszawa
9876543210
Buyer Sp. z o.o.
PL
ul. Fabryczna 3
50-001 Wrocław
2
2
PLN
2026-03-01
FV/002/03/2026
5000.00
5000.00
2
2
1
2
1
1
2
1
VAT
1
Steel scrap (Annex 15)
kg
1000
5.00
5000.00
oo
1
```
`"oo"` is for domestic reverse charge only. For foreign buyers use `"np I"` or `"np II"`; the
validator reports `OO_RATE_FOREIGN_BUYER` otherwise.
---
### Scenario 3: WDT (Intra-EU Supply, 0% VAT)
Supply of goods to an EU-registered business (Wewnątrzwspólnotowa Dostawa Towarów).
Key fields:
- `Podmiot2` uses `KodUE` + `NrVatUE` (not NIP)
- `P_13_6_2` = net value | no VAT | `P_15` = equals `P_13_6_2`
- `FaWiersz/P_12 = "0 WDT"` | `Adnotacje/P_18 = 2`
```xml
FA
3
2026-03-01T10:00:00Z
1234563218
Seller Sp. z o.o.
PL
ul. Eksportowa 5
00-001 Warszawa
DE
123456789
German Buyer GmbH
DE
Musterstraße 1
10115 Berlin
2
2
PLN
2026-03-01
FV/003/03/2026
8000.00
8000.00
2
2
2
2
1
1
2
1
VAT
1
Truck brake assemblies
pcs
4
2000.00
8000.00
0 WDT
GTU_07
```
---
### Scenario 4: Export (Non-EU, 0% VAT)
Export of goods to a country outside the EU.
Key fields:
- `Podmiot2` uses `KodKraju` + `NrID` as siblings in `DaneIdentyfikacyjne`
- `P_13_6_3` = net value | `P_15` = equals `P_13_6_3`
- `FaWiersz/P_12 = "0 EX"` | `Adnotacje/P_18 = 2`
```xml
FA
3
2026-03-01T10:00:00Z
1234563218
Seller Sp. z o.o.
PL
ul. Portowa 8
80-001 Gdańsk
US
12-3456789
US Buyer Inc.
US
123 Main Street
New York, NY 10001
2
2
USD
2026-03-01
FV/004/03/2026
3000.00
3000.00
2
2
2
2
1
1
2
1
VAT
1
Software license
pcs
1
3000.00
3000.00
0 EX
3.9500
```
For foreign currency invoices use `FaWiersz/KursWaluty`, not `Fa/KursWalutyZ`. All amounts in `Fa`
and `FaWiersz` are in the invoice currency. When VAT is charged at a non-zero rate, also provide
`P_14_1W`..`P_14_4W` (VAT converted to PLN; there is no `P_14_5W`); the validator reports `FOREIGN_CURRENCY_TAX_PLN` otherwise.
---
### Scenario 5: VAT Exemption (Zwolnienie)
Invoice for VAT-exempt services or goods (art. 43, 113, 82 of the VAT Act).
Key fields:
- `P_13_7` = net value | no `P_14_x` | `P_15` = equals `P_13_7`
- `FaWiersz/P_12 = "zw"`
- `Adnotacje/Zwolnienie`: set `P_19 = 1` + exactly one of `P_19A`/`P_19B`/`P_19C` (omit `P_19N`)
```xml
FA
3
2026-03-01T10:00:00Z
1234563218
Medical Clinic Sp. z o.o.
PL
ul. Zdrowotna 3
00-001 Warszawa
9876543210
Patient Company Sp. z o.o.
PL
ul. Biurowa 7
00-002 Warszawa
2
2
PLN
2026-03-01
FV/005/03/2026
500.00
500.00
2
2
2
2
1
Art. 43 ust. 1 pkt 19 ustawy z dnia 11 marca 2004 r. o podatku od towarów i usług
1
2
1
VAT
1
Medical consultation
visit
1
500.00
500.00
zw
```
When `P_19 = 1`, omit `P_19N` and include exactly one of `P_19A`/`P_19B`/`P_19C`. The validator
enforces this with `ZWOLNIENIE_LOGIC`.
---
### Scenario 6: Advance Invoice (ZAL) and Settlement Invoice (ROZ)
See `references/advance-invoices.md` for full details. Summary:
ZAL (advance invoice):
- `RodzajFaktury = "ZAL"`; requires a `Zamowienie` element; `FaWiersz` is allowed but optional
- For foreign currency: include `KursWalutyZ` at `Fa` level (valid only for ZAL/KOR_ZAL)
- A ZAL without `Zamowienie` triggers `RODZAJ_FAKTURY_SECTIONS`
ROZ (settlement / final invoice):
- `RodzajFaktury = "ROZ"`; requires a `FakturaZaliczkowa` element referencing the advance invoice(s)
- `FaWiersz` shows the full order; `P_13_x`, `P_14_x` and `P_15` show only the amount still to pay
(totals minus the advances already invoiced); omit `Zamowienie`
- A ROZ without `FakturaZaliczkowa` triggers `RODZAJ_FAKTURY_SECTIONS`
---
### Scenario 7: Corrective Invoice (KOR)
See `references/corrections.md` for full details. Summary:
KOR (corrective invoice):
- `RodzajFaktury = "KOR"`; requires a `DaneFaKorygowanej` element
- P_13_x, P_14_x, P_15 contain the difference (delta), not the corrected total
- A KOR without `DaneFaKorygowanej` triggers `RODZAJ_FAKTURY_SECTIONS`
- Exactly one of `NrKSeF`/`NrKSeFN` must be set (`KOR_NRKSEF_CONSISTENCY`)
---
## Field Reference
### Naglowek
```xml
FA
3
2026-MM-DDTHH:MM:SSZ
```
### Podmiot1 (Seller, always identified by a Polish NIP)
```xml
XXXXXXXXXX
Company name or First Last
PL
Street and number
Postcode and city
```
### Podmiot2 (Buyer): Four Patterns
| Buyer type | Identifier fields | Notes |
|---|---|---|
| Polish company (NIP) | `` | Most common |
| EU buyer with VAT-UE | `` + `` | KodUE is country prefix e.g. `DE` |
| Non-EU buyer | `` + `` | Siblings in DaneIdentyfikacyjne, not nested |
| No tax ID | `1` | Private individuals |
`JST` and `GV` are mandatory in `Podmiot2` (`PODMIOT2_JST_MISSING`, `PODMIOT2_GV_MISSING`); always
include them. A Polish NIP goes in ``, not in `` (`NIP_IN_WRONG_FIELD`).
### Fa: Summary Amount Fields (P_13_x, P_14_x, P_15)
Include only the fields relevant to this transaction and omit zero-value fields.
| Field | Description | Use when |
|---|---|---|
| `P_13_1` | Net at 23% (or 22%) | Domestic 23% sales |
| `P_13_2` | Net at 8% (or 7%) | Domestic 8% sales |
| `P_13_3` | Net at 5% | Domestic 5% sales |
| `P_13_4` | Net, taxi flat rate | Taxis |
| `P_13_5` | Net, OSS procedure | Cross-border digital sales (OSS) |
| `P_13_6_1` | Net 0% domestic (not WDT, not export) | 0% e.g. art. 83 |
| `P_13_6_2` | Net 0% WDT | Intra-EU goods supply |
| `P_13_6_3` | Net 0% export | Goods export to non-EU |
| `P_13_7` | Net, VAT-exempt | VAT exemption |
| `P_13_8` | Net, outside PL (not OSS, not art. 100 pt 4) | Reverse charge non-EU / art.28b/28e |
| `P_13_9` | Net, art. 100 sec. 1 pt 4 services (EU) | Intra-EU service intrastat |
| `P_13_10` | Net, domestic reverse charge | Domestic reverse charge art. 145e |
| `P_13_11` | Net, margin procedure | Margin art. 119/120 |
| `P_14_1..5` | VAT amounts for corresponding P_13 | Only when P_13_x > 0 with a positive rate |
| `P_15` | Total amount due | Always mandatory |
`P_13_8` vs `P_13_9`: services to non-EU entities go in `P_13_8`; services to EU entities covered by
art. 100 sec. 1 pt 4 (VAT-UE summary declaration) go in `P_13_9`.
### Adnotacje: Complete Structure
All sub-elements of `Adnotacje` are required. The three selection blocks each take exactly one
choice:
```xml
2
2
2
2
1
1
2
1
```
`P_18=1` applies to both domestic reverse charge (art. 145e) and cross-border reverse charge
(services outside PL where the buyer accounts for VAT in their country).
### RodzajFaktury Values
| Value | Description |
|---|---|
| `VAT` | Standard invoice |
| `KOR` | Corrective invoice |
| `ZAL` | Advance invoice |
| `ROZ` | Settlement invoice (after advances) |
| `UPR` | Simplified invoice (up to 450 PLN / 100 EUR) |
| `KOR_ZAL` | Corrective advance invoice |
| `KOR_ROZ` | Corrective settlement invoice |
### FaWiersz: Field Order (xs:sequence)
```
NrWierszaFa → UU_ID* → P_6A* → P_7* → Indeks* → GTIN* → PKWIU* → CN* → PKOB*
→ P_8A* → P_8B* → P_9A* → P_9B* → P_10* → P_11* → P_11A* → P_11Vat*
→ P_12* → P_12_XII* → P_12_Zal_15* → KwotaAkcyzy* → GTU* → Procedura*
→ KursWaluty* → StanPrzed*
```
Key FaWiersz fields:
| Field | Description | Notes |
|---|---|---|
| `NrWierszaFa` | Line number (1, 2, 3…) | Mandatory |
| `P_7` | Item/service description (max 512 chars) | Almost always |
| `P_8A` | Unit of measure (e.g. `h`, `pcs`, `kg`) | Optional |
| `P_8B` | Quantity (max 6 decimal places) | Optional |
| `P_9A` | Unit price net (max 8 decimal places) | Optional |
| `P_11` | Net line value (max 2 decimal places) | Optional |
| `P_12` | Tax rate code, see enumeration below | Optional |
| `GTU` | `GTU_01`…`GTU_13` as element value | Optional; max 1 per line |
| `KursWaluty` | NBP exchange rate for this line | Foreign currency invoices only |
| `StanPrzed` | `1` = before-correction state row | Corrective invoices only |
### P_12 Tax Rate Enumeration
Use exactly these values; the validator reports anything else as `P12_ENUMERATION`:
```
"23" 23% (standard rate)
"22" 22%
"8" 8%
"7" 7%
"5" 5%
"4" 4%
"3" 3%
"0 KR" 0%, domestic (not WDT, not export)
"0 WDT" 0%, intra-EU supply (WDT)
"0 EX" 0%, export
"zw" VAT exempt
"oo" domestic reverse charge (art. 145e)
"np I" outside PL territory (not art. 100 pt 4, not OSS): foreign/cross-border reverse charge
"np II" services under art. 100 sec. 1 pt 4: intra-EU services
```
`"NP"`, `"np"`, `"np1"` and `"npI"` are invalid. The space matters: `"np I"`.
### GTU Codes
GTU is a text value in one element: `GTU_12`
- The old format `1` is an XSD error (`GTU_FORMAT`)
- Maximum 1 GTU per line item
- Optional, at the taxpayer's discretion
| Code | Category |
| --- | --- |
| `GTU_01` | Alcoholic beverages (CN 2203-2208) |
| `GTU_02` | Motor fuels (art. 103 ust. 5aa) |
| `GTU_03` | Heating oil and lubricating oils |
| `GTU_04` | Tobacco products, e-cigarette liquid |
| `GTU_05` | Waste (Annex 15 items 79-91) |
| `GTU_06` | Electronic devices, stretch film |
| `GTU_07` | Vehicles and vehicle parts (CN 8701-8708) |
| `GTU_08` | Precious and base metals |
| `GTU_09` | Medicines, medical devices (art. 37av Pharmaceutical Law) |
| `GTU_10` | Buildings, structures, land |
| `GTU_11` | Greenhouse gas emission allowances |
| `GTU_12` | Intangible services: consulting, legal, accounting, marketing, R&D, training |
| `GTU_13` | Transport and warehouse management services (PKWiU 49.4, 52.1) |
### Date Fields
| Field | Scope | When to use |
|---|---|---|
| `Fa/P_6` | All lines | Single delivery/service date for all lines, only when different from P_1 |
| `Fa/OkresFa` (`P_6_Od`+`P_6_Do`) | All lines | Billing period (e.g. monthly subscription) per art. 19a |
| `FaWiersz/P_6A` | Per line | Different dates on different lines |
When the service/delivery date equals the invoice date (`P_1`), leave `P_6` out. `P_6` and `P_6A`
are mutually exclusive (`P6_P6A_MUTUAL_EXCLUSION`).
### Decimal Precision
| Fields | Max decimal places | Example |
|---|---|---|
| P_11, P_13_x, P_14_x, P_15 (general amounts) | 2 | `1230.50` |
| P_9A, P_9B (unit prices) | 8 | `75.12345678` |
| P_8B (quantities) | 6 | `80.123456` |
| KursWaluty, KursWalutyZ (exchange rates) | 6 | `3.707500` |
Use `.` as the decimal separator and no thousand separators (`DECIMAL_PRECISION`,
`AMOUNT_NO_SEPARATORS`).
### Payment (Platnosc, optional)
```xml
YYYY-MM-DD
6
PL49...
BREXPLPWMBK
mBank S.A.
```
FormaPlatnosci values: 1=cash, 2=card, 3=voucher, 4=cheque, 5=credit, 6=bank transfer, 7=mobile
---
## Validator Issue Codes
Each semantic issue has a `code` (the CLI prints `Code: `) and a severity. Errors make the
invoice invalid; warnings do not. Use the code to find the rule that was broken.
### Podmiot
| Code | Severity | Rule |
|---|---|---|
| `PODMIOT2_JST_MISSING` | error | `JST` is mandatory in `Podmiot2` |
| `PODMIOT2_GV_MISSING` | error | `GV` is mandatory in `Podmiot2` |
| `JST_REQUIRES_PODMIOT3` | error | `JST=1` requires a `Podmiot3` with `Rola=8` |
| `GV_REQUIRES_PODMIOT3` | error | `GV=1` requires a `Podmiot3` with `Rola=10` |
| `NIP_IN_WRONG_FIELD` | warning | A Polish NIP (10 digits) belongs in `NIP`, not `NrVatUE` |
| `PODMIOT3_UDZIAL_REQUIRES_ROLE_4` | error | `Udzial` is allowed only with `Rola=4` |
| `PODMIOT3_ROLE_MISSING` | error | `Podmiot3` needs `Rola`, or `RolaInna` with `OpisRoli` |
| `SELF_BILLING_PODMIOT3_CONFLICT` | warning | Self-billing (`P_17=1`) conflicts with a `Podmiot3` with `Rola=5` |
### Fa core
| Code | Severity | Rule |
|---|---|---|
| `P15_MISSING` | error | `P_15` is mandatory |
| `P6_P6A_MUTUAL_EXCLUSION` | error | `Fa/P_6` and `FaWiersz/P_6A` cannot both be present |
| `RODZAJ_FAKTURY_SECTIONS` | error | KOR, KOR_ZAL and KOR_ROZ need `DaneFaKorygowanej`; ZAL needs `Zamowienie`; ROZ needs `FakturaZaliczkowa` |
| `KURS_WALUTY_Z_PLACEMENT` | error | `Fa/KursWalutyZ` is only for ZAL and KOR_ZAL |
| `FOREIGN_CURRENCY_TAX_PLN` | warning | Foreign currency with VAT at `P_13_1`..`P_13_4` needs the matching `P_14_xW` (PLN) |
### Adnotacje
| Code | Severity | Rule |
|---|---|---|
| `ADNOTACJE_P16_MISSING` | error | `P_16` is mandatory |
| `ADNOTACJE_P17_MISSING` | error | `P_17` is mandatory |
| `ADNOTACJE_P18_MISSING` | error | `P_18` is mandatory |
| `ADNOTACJE_P18A_MISSING` | error | `P_18A` is mandatory |
| `ADNOTACJE_ZWOLNIENIE_MISSING` | error | `Zwolnienie` is mandatory |
| `ADNOTACJE_NST_MISSING` | error | `NoweSrodkiTransportu` is mandatory |
| `ADNOTACJE_P23_MISSING` | error | `P_23` is mandatory |
| `ADNOTACJE_PMARZY_MISSING` | error | `PMarzy` is mandatory |
| `ZWOLNIENIE_LOGIC` | error | Exactly one of `P_19`/`P_19N` is 1; with `P_19=1`, exactly one of `P_19A`/`P_19B`/`P_19C` |
| `NST_LOGIC` | error | Exactly one of `P_22`/`P_22N`; with `P_22=1`, `P_42_5` and `NowySrodekTransportu` are required |
| `PMARZY_LOGIC` | error | Exactly one of `P_PMarzy`/`P_PMarzyN`; with `P_PMarzy=1`, exactly one margin type |
### FaWiersz
| Code | Severity | Rule |
|---|---|---|
| `P12_ENUMERATION` | error | `P_12` must be one of the 14 valid codes |
| `OO_RATE_FOREIGN_BUYER` | warning | `"oo"` is domestic only; foreign buyers need `"np I"` or `"np II"` |
| `GTU_FORMAT` | error | `GTU` must be `GTU_01`..`GTU_13` as the element value |
| `DECIMAL_PRECISION` | error | Amounts, prices, quantities and rates respect their decimal limits |
### Corrective invoices and reverse charge
| Code | Severity | Rule |
|---|---|---|
| `KOR_NRKSEF_CONSISTENCY` | error | Exactly one of `NrKSeF`/`NrKSeFN` is 1; with `NrKSeF=1`, `NrKSeFFaKorygowanej` is required |
| `REVERSE_CHARGE_CONSISTENCY` | warning | `P_13_8`/`P_13_10` present requires `P_18=1`; `P_18=1` requires lines with `np I`, `np II` or `oo` |
### Payment and transaction
| Code | Severity | Rule |
|---|---|---|
| `PAYMENT_ZAPLACONO_DATE` | warning | `Zaplacono=1` requires `DataZaplaty` |
| `RACHUNEKBANKOWY_NRRB` | error | A non-empty `RachunekBankowy` needs `NrRB` |
| `NRRB_LENGTH` | warning | `NrRB` is 10 to 34 characters |
| `IPKSEF_FORMAT` | warning | `IPKSeF` is exactly 13 alphanumeric characters |
| `WALUTA_UMOWNA_PLN` | error | `WalutaUmowna` is never `PLN` |
| `KURS_WALUTA_PAIR` | error | `KursUmowny` and `WalutaUmowna` are both present or both absent |
| `TRANSPORT_MINIMUM_DATA` | warning | `Transport` needs the transport type and a cargo description |
### Format and additional checks
| Code | Severity | Rule |
|---|---|---|
| `AMOUNT_NO_SEPARATORS` | error | No thousand separators; `.` is the only decimal separator |
| `TAX_CALCULATION_MISMATCH` | error | `P_14_x` matches `P_13_x` times the rate and `P_15` equals the sum of all `P_13_x` and `P_14_x` (not checked on corrective invoices) |
| `INVALID_BANK_ACCOUNT_FORMAT` | error | A `PL` IBAN is 28 characters; a bare NRB is 26 digits |
| `DUPLICATE_LINE_NUMBERS` | error | `NrWierszaFa` is unique (corrective invoices excepted) |
| `NEGATIVE_QUANTITY_NOT_ALLOWED` | error | Negative `P_8B` only on corrective invoice types |
| `CURRENCY_RATE_MISMATCH` | warning | `KursWaluty` differs from the NBP mid-rate for the date required by art. 31a of the VAT Act |
| `CURRENCY_RATE_UNVERIFIABLE` | warning | The NBP rate could not be fetched or checked |
KSeF rejects XML that contains processing instructions, a UTF-8 BOM, a non-UTF-8 declared
encoding, or W3C-discouraged Unicode characters (`XML_PROCESSING_INSTRUCTION`, `XML_BOM_PRESENT`,
`XML_ENCODING_NOT_UTF8`, `XML_DISCOURAGED_CHARACTER`): test and demo already do, production from
19 October 2026. Emit plain UTF-8 without them.
---
## Common Errors and Fixes
| Error | Cause | Fix |
|---|---|---|
| `PODMIOT2_JST_MISSING` / `PODMIOT2_GV_MISSING` | Both elements are mandatory | Add `22` to `Podmiot2` |
| "KursWalutyZ not expected" | `KURS_WALUTY_Z_PLACEMENT`: only ZAL/KOR_ZAL may use it | Remove it from `Fa`; use `FaWiersz/KursWaluty` |
| "NP not in enumeration" | `P12_ENUMERATION`: "NP" is not a valid `P_12` value | Use `"np I"` or `"np II"` (with a space) |
| `1` XSD error | `GTU_FORMAT`: wrong GTU format | Use `GTU_12` |
| "not expected, expected X" in `FaWiersz` | XSD sequence error | `GTU` must come before `KursWaluty` and `StanPrzed` |
| "NazwaBank not expected" | Typo in element name | The correct name is `NazwaBanku` |
| Reverse charge with wrong `P_18` | `REVERSE_CHARGE_CONSISTENCY` | Set `P_18=1` when using `"oo"`, `"np I"` or `"np II"` |
| `P_13_x` = 0 causing issues | The schema expects no zero-value `P_13_x` | Omit any `P_13_x` field with a zero value |
| "minOccurs" error on `Adnotacje` | `ADNOTACJE_*_MISSING`: incomplete block | Include all sub-elements: `Zwolnienie`, `NoweSrodkiTransportu`, `PMarzy` and the rest |
| `P_19` and `P_19N` both set | `ZWOLNIENIE_LOGIC`: mutual exclusion | Use `P_19N=1` or `P_19=1` with one of `P_19A`/`P_19B`/`P_19C` |
| Polish NIP in `NrVatUE` | `NIP_IN_WRONG_FIELD` | Move the 10-digit NIP to the `` element |