KSeF checks syntax.
The law demands substance.
We check both.

KSeF validates FA(3) XML. Polish tax law and official FA(3) guidance define obligations that schema validation alone does not prove. KSeF Guard checks 128 active validation rules offline before submission.

Download Free — ~30 MB See exported sample report (PDF) →

FA(3) v13775 128 rules Offline — data stays on disk

128 validation rules · Source-backed evidence ksefguard.pl/en/features →

KSeF Guard

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3 OK|6 ERR•9 total

Użycie:Usage:9/∞

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Click any FAIL file to see the report ↓

FA_2026_01_0201.xml

KSEF-BUS-044+1

FAIL

FA_2026_02_0042.xml

KSEF-BUS-003+3

FAIL

FA_2026_02_0099.xml

KSEF-BUS-030

FAIL

FA_2026_02_0187.xml

KSEF-BUS-006+2

FAIL

FA_2026_03_0001.xml

Zgodny | Valid

PASS

FA_2026_03_0015.xml

Zgodny | Valid

PASS

FA_2026_03_0078.xml

KSEF-BUS-072+1

FAIL

FA_2026_03_0156.xml

1 XSD· KSEF-BUS-124+1

FAIL

FA_KOR_2026_01_003.xml

Zgodny | Valid

PASS

XML File:FA_2026_02_0042.xml

3 Errors + 1 warnRisk 65%

Reguła | Rule: KSEF-BUS-003

ERRORGOVCross-field logic

PROBLEM

Faktura wystawiona w walucie obcej nie zawiera pola P_14_1W (kwota VAT przeliczona na PLN). Pole to jest wymagane dla każdego koszyka stawki z VAT walutowym.

Foreign currency invoice is missing the P_14_1W field (VAT amount converted to PLN). This field is required for each rate bracket that has foreign-currency VAT.

CO NAPRAWIĆ | WHAT TO FIX

Otwórz fakturę walutową i uzupełnij pole P_14_1W kwotą VAT przeliczoną na PLN (wg kursu właściwego dla faktury, zgodnie z art. 31a ustawy o VAT) w sekcji podsumowania.

Open the foreign currency invoice and fill P_14_1W with VAT converted to PLN (using the conversion rate applicable to the invoice per Art. 31a of the VAT Act) in the summary section.

Dowód | Evidence

Wartość | ValueKodWaluty=EUR

Ścieżka | Path/Faktura/Fa/P_14_1W

Podgląd źródła | Source Preview
Brakujący | MissingLine 41
38      <P_8A>h</P_8A><P_8B>50.00</P_8B><P_9A>100.00</P_9A><P_9B>123.00</P_9B>
39      <P_11>5000.00</P_11><P_11A>6150.00</P_11A><P_11Vat>1150.00</P_11Vat><P_12>23</P_12>
40    </FaWiersz>
41  </Fa>
  ← dodaj <P_14_1W> tutaj | add <P_14_1W> here
42</Faktura>

ŹRÓDŁO PRAWNE | LEGAL SOURCE

Pokaż źródło

Pola P_14_1W, P_14_2W, P_14_3W i P_14_4W są wymagane, gdy faktura jest wystawiona w walucie obcej. Każde pole zawiera kwotę podatku przeliczoną na PLN zgodnie z art. 106e ust. 11 ustawy o VAT — odpowiednio dla stawki podstawowej (23%/22%), obniżonej pierwszej (8%/7%), obniżonej drugiej (5%) oraz ryczałtu taksówkowego. Pole P_14_*W musi być obecne dla każdego koszyka stawki (P_14_*), który występuje na fakturze.

Broszura FA(3), Tabela 26 — P_14_1W..P_14_4W, Page 47

Show Source

Fields P_14_1W, P_14_2W, P_14_3W and P_14_4W are required when the invoice is issued in foreign currency. Each field contains the tax amount converted to PLN in accordance with Art. 106e sec. 11 of the VAT Act — for the basic rate (23%/22%), first reduced rate (8%/7%), second reduced rate (5%), and taxi lump sum respectively. The P_14_*W field must be present for each rate bracket (P_14_*) that appears on the invoice.

Brochure FA(3), Table 26 — P_14_1W..P_14_4W, Page 48

PODSTAWA PRAWNA | LEGAL BASIS (2)

Reguła | Rule: KSEF-BUS-005

ERRORGOVVerbatim legal quote

PROBLEM

Faktura walutowa zawiera kwoty VAT w walucie obcej, ale nie ma żadnego przeliczenia VAT na złotówki (pola P_14_*W). Art. 106e ust. 11 ustawy o VAT wymaga wykazywania kwot podatku w PLN.

Foreign currency invoice has VAT amounts in the foreign currency, but no PLN VAT conversion (P_14_*W fields) is present. Art. 106e sec. 11 of the VAT Act requires tax amounts to be presented in PLN.

CO NAPRAWIĆ | WHAT TO FIX

Otwórz fakturę walutową i dodaj przeliczenie VAT na PLN (pole P_14_*W) dla każdego koszyka stawki, który zawiera VAT walutowy.

Open the foreign currency invoice and add PLN VAT conversion (P_14_*W field) for each rate bracket that contains foreign-currency VAT.

Dowód | Evidence

Wartość | ValueKodWaluty=EUR

Ścieżka | Path/Faktura/Fa/P_14_*W

Podgląd źródła | Source Preview
Brakujący | MissingLine 41
38      <P_8A>h</P_8A><P_8B>50.00</P_8B><P_9A>100.00</P_9A><P_9B>123.00</P_9B>
39      <P_11>5000.00</P_11><P_11A>6150.00</P_11A><P_11Vat>1150.00</P_11Vat><P_12>23</P_12>
40    </FaWiersz>
41  </Fa>
  ← dodaj <P_14_1W> tutaj | add <P_14_1W> here
42</Faktura>

ŹRÓDŁO PRAWNE | LEGAL SOURCE

Pokaż źródło

“11. Kwoty podatku wykazuje się w złotych. Kwoty podatku wyrażone w walucie obcej wykazuje się w złotych przy zastosowaniu zasad przeliczania na złote przyjętych dla przeliczania kwot stosowanych do określenia podstawy opodatkowania. Kwoty wykazywane w fakturze zaokrągla się do pełnych groszy, przy czym końcówki poniżej 0,5 grosza pomija się, a końcówki od 0,5 grosza zaokrągla się do 1 grosza.”

Ustawa o VAT Art. 106e ust. 11, Page 126

Show Source

“11. Tax amounts shall be shown in Polish zlotys. Tax amounts expressed in foreign currency shall be shown in zlotys using the conversion rules adopted for converting amounts used to determine the tax base. Amounts shown on the invoice shall be rounded to full groszy; fractions below 0.5 grosze are dropped, while fractions of 0.5 grosze or more are rounded up to 1 grosze.”

VAT Act, Art. 106e sec. 11, Page 126

PODSTAWA PRAWNA | LEGAL BASIS (1)

Reguła | Rule: KSEF-BUS-114

ERRORGOVCross-field logic

PROBLEM

Faktura walutowa ma wypełnioną kwotę VAT w walucie (P_14_* — kwota VAT), ale brak odpowiadającego przeliczenia na PLN (P_14_*W — kwota VAT w PLN). KSeF wymaga prezentacji VAT w złotówkach.

Foreign currency invoice has a VAT amount populated (P_14_* — VAT amount), but the corresponding PLN conversion (P_14_*W — PLN VAT amount) is missing. KSeF requires VAT to be presented in Polish zloty.

CO NAPRAWIĆ | WHAT TO FIX

Uzupełnij brakujące pole przeliczenia VAT na PLN (P_14_*W) — kwota powinna wynosić: kurs wymiany × kwota VAT w walucie obcej.

Fill in the missing PLN VAT conversion field (P_14_*W) — the amount should be: exchange rate × foreign currency VAT amount.

Dowód | Evidence

Wartość | ValueKodWaluty=EUR; bucket=P_14_1W

Ścieżka | Path/Faktura/Fa/P_14_*W

Podgląd źródła | Source Preview
Brakujący | MissingLine 41
37      <NrWierszaFa>1</NrWierszaFa><P_7>Consulting services</P_7>
38      <P_8A>h</P_8A><P_8B>50.00</P_8B><P_9A>100.00</P_9A><P_9B>123.00</P_9B>
39      <P_11>5000.00</P_11><P_11A>6150.00</P_11A><P_11Vat>1150.00</P_11Vat><P_12>23</P_12>
40    </FaWiersz>
41  </Fa>
  ← dodaj <P_14_1W> tutaj | add <P_14_1W> here
42</Faktura>

ŹRÓDŁO PRAWNE | LEGAL SOURCE

Pokaż źródło

Dla waluty obcej kazde pole P_14_x musi mieć odpowiadajace P_14_xW.

UoVAT, Art. 31a ust. 1, Page 43

Show Source

For foreign currency invoices, each non-zero P_14_x bucket must have corresponding P_14_xW conversion.

VAT Act, Art. 31a sec. 1, Page 43

PODSTAWA PRAWNA | LEGAL BASIS (4)

Reguła | Rule: KSEF-BUS-197

WARNHEURBusiness logic

PROBLEM

Faktura ma datę wystawienia (P_1) w weekend (sobota lub niedziela). Wystawienie faktury w weekend jest rzadkie i może wskazywać na błąd daty lub zautomatyzowany proces.

Invoice has issue date (P_1) on a weekend (Saturday or Sunday). Weekend issuance is unusual and may indicate a date entry error or automated process.

CO NAPRAWIĆ | WHAT TO FIX

Sprawdź datę wystawienia faktury — zwykle faktury są wystawiane w dni robocze. Jeśli data jest poprawna, może to być uzasadnione specjalnym procesem biznesowym.

Check the invoice issue date — invoices are typically issued on business days. If the date is correct, it may be justified by a special business process.

Dowód | Evidence

Wartość | ValueKSEF-BUS-197_WEEKEND_ISSUE: P_1=2026-02-15 is Sunday

Ścieżka | Path/Faktura/Fa/P_1

Podgląd źródła | Source Preview
Line 24
</Podmiot2>
<Fa>
  <KodWaluty>EUR</KodWaluty>
  <P_1>2026-02-15</P_1>
    ✓ P_1 → dzień roboczy / weekday
  <P_2>FV/2026/02/0042</P_2>
  <P_13_1>5000.00</P_13_1><P_14_1>1150.00</P_14_1>
  <P_15>6150.00</P_15><KursWalutyZ>4.2700</KursWalutyZ>

ŹRÓDŁO PRAWNE | LEGAL SOURCE

Pokaż źródło

Wystawienie faktury w weekend (sobota, niedziela) jest nietypowe i może wskazywać na błąd daty lub zautomatyzowany proces bez kontroli.

KSeF Guard heuristic (weekend invoice issuance — gateway validation practice)

Show Source

Invoice issuance on weekends (Saturday, Sunday) is unusual and may indicate a date entry error or automated process without human review.

KSeF Guard heuristic (weekend invoice issuance — gateway validation practice)

PODSTAWA PRAWNA | LEGAL BASIS (1)

What a KSeF rejection actually costs you

Invoice date shifts

Your invoice is legally dated when KSeF accepts it, not when you sent it. A rejection on the 10th fixed on the 12th means your invoice is dated the 12th.

VAT period disruption

Shifted dates push invoices into the next reporting period, creating discrepancies between your accounting system, KSeF, and the JPK_VAT filing.

Batch blocking

One invalid invoice in a batch submission blocks the entire set. Hundreds of invoices delayed by a single error.

256

Invoices tested on official KSeF API

107

Additional catches beyond KSeF — and growing

False negatives

Gov-enforced rules

We submitted 256 invoices to the official KSeF test API. It accepted 98 non-compliant invoices that should have been caught. KSeF Guard flags all 107 rules the API misses — 55 legal requirements, 52 best-practice and security.

Structural errors caught first

Before any business rules run, KSeF Guard validates your XML against the official FA(3) schema — catching the structural errors that cause immediate KSeF rejection.

FA_2026_03_0001.xml

Valid

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<?xml version="1.0" encoding="UTF-8"?>

<SystemInfo>KSeF Guard Showcase</SystemInfo>

</Naglowek>

<Adres><KodKraju>PL</KodKraju><AdresL1>ul. Marszalkowska 1, Warszawa</AdresL1></Adres>

</Podmiot1>

<Nazwa>XYZ Trading Sp. z o.o.</Nazwa>

</DaneIdentyfikacyjne>

<Adres><KodKraju>PL</KodKraju><AdresL1>ul. Poznanska 10, Poznan</AdresL1></Adres>

</Podmiot2>

<Fa>

<P_1>2026-03-10</P_1>

<P_2>FV/2026/03/0001</P_2>

<P_13_1>1000.00</P_13_1><P_14_1>230.00</P_14_1>

<P_15>1230.00</P_15>

<P_16>2</P_16><P_17>2</P_17><P_18>2</P_18><P_18A>2</P_18A>

<P_23>2</P_23>

</Adnotacje>

<NrWierszaFa>1</NrWierszaFa><P_7>Uslugi konsultingowe IT</P_7>

<P_8A>godz</P_8A><P_8B>10.00</P_8B><P_9A>100.00</P_9A><P_9B>123.00</P_9B>

<P_11>1000.00</P_11><P_11A>1230.00</P_11A><P_11Vat>230.00</P_11Vat><P_12>23</P_12>

</FaWiersz>

</Fa>

</Faktura>

FA_2026_03_0156.xml

XSD Error

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<?xml version="1.0" encoding="UTF-8"?>

<Faktura xmlns:etd="http://crd.gov.pl..." xmlns:xsi="http://www.w3.org..."

xmlns="http://crd.gov.pl...">

<SystemInfo>KSeF Guard Showcase</SystemInfo>

</Naglowek>

↳ Fix: NIP must be exactly 10 digits without dashes — e.g. 9999999999

<Nazwa>TechStar Sp. z o.o.</Nazwa>

</DaneIdentyfikacyjne>

<Adres>

<AdresL1>ul. Wspolna 30, Wroclaw</AdresL1>

</Adres>

</Podmiot1>

<Nazwa>DataCenter Sp. z o.o.</Nazwa>

</DaneIdentyfikacyjne>

<Adres>

<AdresL1>ul. Serwerowa 5, Poznan</AdresL1>

</Adres>

</Podmiot2>

<Fa>

<P_1>2026-03-18</P_1>

<P_2>FV/2026/03/0156</P_2>

<P_13_1>1666.66</P_13_1>

<P_14_1>383.33</P_14_1>

<P_13_3>0.95</P_13_3>

<P_14_3>0.05</P_14_3>

<P_15>2051.00</P_15>

<P_16>2</P_16>

<P_17>2</P_17>

<P_18>2</P_18>

<P_18A>2</P_18A>

<P_19N>1</P_19N>

</Zwolnienie>

<P_22N>1</P_22N>

</NoweSrodkiTransportu>

<P_23>2</P_23>

<P_PMarzyN>1</P_PMarzyN>

</PMarzy>

</Adnotacje>

<P_7>Serwery i osprzet sieciowy</P_7>

<P_8A>szt</P_8A>

<P_8B>1</P_8B>

<P_9A>1626.01</P_9A>

<P_11>1626.01</P_11>

<P_12>23</P_12>

</FaWiersz>

<P_7>Konfiguracja i wniesienie sprzetu</P_7>

<P_8A>szt</P_8A>

<P_8B>1</P_8B>

<P_9A>40.65</P_9A>

<P_11>40.65</P_11>

<P_12>23</P_12>

</FaWiersz>

<P_7>Kabel sieciowy promocyjny</P_7>

<P_8A>szt</P_8A>

<P_8B>1</P_8B>

<P_9A>0.95</P_9A>

<P_11>0.95</P_11>

<P_12>5</P_12>

</FaWiersz>

</Platnosc>

</Fa>

</Faktura>

PASS FA_2026_03_0001.xml FAIL FA_2026_03_0156.xml

XSD Error Line 14: NIP pattern violation — expected [0-9]{10}, got 999-999-99-99

XSD: schema FA(3) 1-0E • 128 rules • libxml2

128 active validation rules with source-backed evidence

Rules trace back to Art. 106e of the VAT Act, Ministry of Finance regulations, or the official FA(3) brochure. SHA-256 verified source quotes — not paraphrases.

Rule Explorer 128 rules

Search rules...

Rule ID

Description

Classification

KSeF Gov Enforced

Severity

KSEF-BUS-003

All P_14_*W fields required for foreign currency in corresponding rate brackets

GOV_MANDATED

ERROR

KSEF-BUS-006

Exchange rate missing for foreign currency invoice

GOV_MANDATED

ERROR

KSEF-BUS-030

Invoice issue date exceeds the allowed future-date window

GOV_MANDATED

KSeF Gov Enforced

ERROR

KSEF-BUS-044

Line net value consistent with quantity × adjusted unit price

GOV_MANDATED

ERROR

KSEF-BUS-072

Tax rate must be consistent with net amount bucket (simplified invoices exempt)

BEST_PRACTICE

ERROR

KSEF-BUS-074

P_19=1 without providing exemption basis (P_19A/B/C)

GOV_MANDATED

KSeF Gov Enforced

ERROR

↓ 122 more rules

KSEF-BUS-003 GOV MANDATED ERROR KSEF GUARD ONLY

All P_14_*W fields required for foreign currency in corresponding rate brackets

Wszystkie pola P_14_*W wymagane dla waluty obcej w odpowiednich przedziałach stawek

Problem

Foreign currency invoice is missing a P_14_*W field (VAT amount converted to PLN) for at least one rate bracket that has foreign-currency VAT.

How to Fix

Open the foreign currency invoice and fill in the missing P_14_*W field (P_14_1W, P_14_2W, P_14_3W, or P_14_4W) with VAT converted to PLN (using the conversion rate applicable to the invoice per Art. 31a of the VAT Act) in the summary section.

Source Quote

”Fields P_14_1W, P_14_2W, P_14_3W and P_14_4W are required when the invoice is issued in foreign currency. Each field contains the tax amount converted to PLN in accordance with Art. 106e sec. 11 of the VAT Act — for the basic rate (23%/22%), first reduced rate (8%/7%), second reduced rate (5%), and taxi lump sum respectively. The P_14_*W field must be present for each rate bracket (P_14_*) that appears on the invoice.”

DESCRIPTION SHA-256: ac9125634746…

KSEF-BUS-006 GOV MANDATED ERROR KSEF GUARD ONLY

Exchange rate missing for foreign currency invoice

Brak kursu waluty dla faktury w walucie obcej

Problem

Foreign currency invoice has VAT amounts in foreign currency (P_14_*W), but no exchange rate is provided. Either KursWalutyZ (global invoice rate) or KursWaluty (per-line rate) must be specified.

How to Fix

Provide the exchange rate in KursWalutyZ (global rate for the entire invoice) or KursWaluty (per-line rate). The rate should follow Art. 31a — the average NBP rate from the last business day before the tax obligation arises.

Source Quote

“The exchange rate used to calculate the amount of tax, in cases referred to in sec. VI of the Act. When amounts used for determining the tax base are provided in a foreign currency, the exchange rate applicable to a given line of the invoice shall be indicated.”

DESCRIPTION SHA-256: c2fd221e087382ca…

KSEF-BUS-030 GOV MANDATED ERROR KSeF GOV ENFORCED

Invoice issue date exceeds the allowed future-date window

Data wystawienia przekracza dozwolone okno przyszłej daty

Problem

Invoice issue date (P_1) is set in the future beyond the allowed window. The evaluator applies a 30-day forward threshold from the reference date as a safeguard against obvious date errors.

How to Fix

Check the invoice issue date (P_1). The statutory requirement (Art. 106i) defines invoice issuance deadlines; the 30-day threshold is an evaluator tolerance preventing obvious date errors.

Source Quote

“Art. 106na sec. 1 of the Act stipulates that a structured invoice is deemed to have been issued on the date it is sent to KSeF. The date of issue of the structured invoice indicated by the taxpayer in field P_1 is consistent with the date of sending the invoice to KSeF.”

DESCRIPTION SHA-256: fde059cc6450d9de…

KSEF-BUS-044 GOV MANDATED ERROR KSEF GUARD ONLY

Line net value consistent with quantity × adjusted unit price

Wartość netto wiersza spójna z ilością × skorygowana cena jednostkowa

Problem

Line net value (P_11) does not match the product of quantity and unit price adjusted for discounts/surcharges. The evaluator verifies the formula: P_11 ≈ P_8B × (P_9A − P_10 + P_10_Dodatki) with ±0.02 PLN tolerance.

How to Fix

Check the invoice line calculation. The legal basis requires disclosure of: quantity (P_8B), net unit price (P_9A), and net value (P_11). The evaluator verifies arithmetic consistency of these fields accounting for discount (P_10) and surcharge (P_10_Dodatki).

Source Quote

“11) Value of goods delivered or services provided covered by the transaction, excluding tax amount (net sales value)”

VERBATIM SHA-256: 2a85116fe70ae9ce…

KSEF-BUS-072 BEST PRACTICE ERROR KSEF GUARD ONLY

Tax rate must be consistent with net amount bucket (simplified invoices exempt)

Stawka podatku musi być zgodna z przedziałem kwot netto (faktury uproszczone pominięte)

Problem

Invoice line VAT rate (P_12 — VAT rate) does not have a matching net summary bucket (P_13_*). Each applied rate must have its corresponding bucket in the summary. This rule does not apply to simplified invoices (UPR).

How to Fix

Recalculate the invoice summary. Rate-to-bucket mapping: 23%/22% -> P_13_1, 8%/7% -> P_13_2, 5% -> P_13_3, zw (exempt) -> P_13_7, oo (reverse charge) -> P_13_10, 0% -> P_13_6_*.

Source Quote

“Tax rates from line items (P_12) must be consistent with the breakdown of net sales values in the summary fields according to rates (P_13_*).”

DESCRIPTION SHA-256: c431900779d346a3…

KSEF-BUS-074 GOV MANDATED ERROR KSeF GOV ENFORCED

P_19=1 without providing exemption basis (P_19A/B/C)

P_19=1 bez podania podstawy zwolnienia (P_19A/B/C)

Problem

Invoice has VAT exemption (P_19 set) but none of the legal basis fields (P_19A, P_19B, P_19C) are populated.

How to Fix

Fill at least one field: P_19A (VAT Act provision), P_19B (provision of Directive 2006/112/EC), or P_19C (other legal basis).

Source Quote

”If P_19='1' (VAT exemption), at least one of P_19A (act provision), P_19B (Directive 2006/112/EC provision), or P_19C (other legal basis) must be filled in, indicating the legal basis for the exemption.”

DESCRIPTION SHA-256: 794cdd84f1c9468b…

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KSeF Guard

Validation Report

Date: 2026-05-03

KSeF Guard

Walidator FA(3)

Executive Summary

Files

PASS

FAIL

Pass Rate

17%

Rules evaluated: 128 | Errors: 9 | Warnings: 4 | XSD: 1

File Index

#	Status	Filename	Błędy	Ostrz.	XSD	Risk	Str.
1	FAIL	FA_2026_01_0201.xml	1	1	0	25	1
2	FAIL	FA_2026_02_0042.xml	3	1	0	65	2
3	FAIL	FA_2026_02_0099.xml	1	1	0	25	4
4	FAIL	FA_2026_02_0187.xml	2	1	0	25	6
5	PASS	FA_2026_03_0001.xml	0	0	0	0	7
6	FAIL	FA_2026_03_0156.xml	2	0	1	40	9

FAIL FA_2026_01_0201.xml Errors: 1 | Warnings: 1

[ERROR] KSEF-BUS-044 Legal

Problem:

Line net value (P_11 — net amount) does not match the formula: quantity (P_8B) × (unit price P_9A − discount P_10 + surcharge P_10_Dodatki). Please check the line calculation.

What to fix:

Check the invoice line calculations — the net amount (P_11) should equal P_8B × (P_9A − P_10 + P_10_Dodatki), rounded to grosz (tolerance: 0.02 PLN).

Evidence:

Value: NrWierszaFa=2; P_8B=10.00; P_9A=50.00; P_11=0.00

Path: /Faktura/Fa/FaWiersz/P_11

Line: 44

XML Preview Line 44

41<FaWiersz>

42 <NrWierszaFa>2</NrWierszaFa><P_7>Instalacja paneli</P_7>

43 <P_8A>szt</P_8A><P_8B>10.00</P_8B><P_9A>50.00</P_9A><P_9B>0.00</P_9B>

44 <P_11>0.00</P_11><P_11A>0.00</P_11A><P_11Vat>0.00</P_11Vat><P_12>23</P_12>

45</FaWiersz>

Fix: P_11 = 500.00

Quote:

"11) Value of goods delivered or services provided covered by the transaction, excluding tax amount (net sales value)"

Source: Ustawa o VAT Art. 106e ust. 1 pkt 11

TXT Expand

ksef-guard v1.0.0 | Preset: recommended | 128 rules

────────────────────────────────────────────────────

✗ FA_2026_01_0201.xml — FAIL

XSD: pass | Rules: 128 evaluated, 1 error(s), 1 warning(s)

[FAIL] KSEF-BUS-044 [GOV_MANDATED]

Problem: Wartość netto wiersza (P_11 — kwota netto) nie odpowiada formule…

Line net value (P_11 — net amount) does not match the formula…

Fix:Sprawdź obliczenia na pozycjach faktury — wartość netto (P_11)…

Check the invoice line calculations — the net amount (P_11)…

Evidence: NrWierszaFa=2; P_8B=10.00; P_9A=50.00; P_11=0.00

Path:/Faktura/Fa/FaWiersz/P_11

Source:Ustawa o VAT Art. 106e ust. 1 pkt 11

[WARN] KSEF-BUS-140 [BEST_PRACTICE]

Problem: Pozycja faktury ma zerową kwotę netto (P_11 — kwota netto = 0) przy stawce opodatkowanej…

Invoice line has zero net amount (P_11 — net amount = 0) with a taxable rate…

✗ FA_2026_02_0042.xml — FAIL

✗ FA_2026_02_0099.xml — FAIL

✗ FA_2026_02_0187.xml — FAIL

✓ FA_2026_03_0001.xml — PASS

✗ FA_2026_03_0156.xml — FAIL

────────────────────────────────────────────────────

Summary: 1 pass, 5 fail (6 files) in 285ms

Schema: FA(3) 1-0E | Registry: 1.0.0

CSV Expand

file_name	file_status	risk_score	violation_type	code	severity	classification
FA_2026_01_0201.xml	FAIL	25	RULE	KSEF-BUS-044	error	GOV_MANDATED
FA_2026_02_0042.xml	FAIL	65	RULE	KSEF-BUS-003	error	GOV_MANDATED
FA_2026_02_0099.xml	FAIL	25	RULE	KSEF-BUS-030	error	GOV_MANDATED
FA_2026_02_0187.xml	FAIL	25	RULE	KSEF-BUS-006	error	GOV_MANDATED
FA_2026_03_0001.xml	PASS	0	-	-	-	-
FA_2026_03_0156.xml	FAIL	40	XSD	FA3-XSD-E001	error	-

15 rows · 18 columns · UTF-8 BOM

JSON Expand

{

"rule_id": "KSEF-BUS-044",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"source_ref": "Ustawa o VAT Art. 106e ust. 1 pkt 11",

"problem_pl": "Wartość netto wiersza (P_11)…",

"problem_en": "Line net value (P_11 — net amount)…",

"reason_code": "KSEF-BUS-044_LINE_ARITHMETIC_MISMATCH|xml_line=44",

"fix_pl": "Sprawdź obliczenia na pozycjach…",

"fix_en": "Check the invoice line calculations…",

"quote_pl": "11) wartość dostarczonych towarów…",

"quote_en": "11) Value of goods delivered…",

"evidence_value": "NrWierszaFa=2; P_8B=10.00…",

"evidence_path": "/Faktura/Fa/FaWiersz/P_11",

"evidence_line": 44,

"correction_hint": "P_11 = 500.00",

"legal_basis": [

{ "title_pl": "Wymogi ustawowe…", "source": "Art. 106e ust. 1 pkt 8", … }

]

}

TXT .\ksef-guard.exe validate --preset recommended --format text Documents\Invoices

ksef-guard v1.0.0 | Preset: recommended | 128 rules

────────────────────────────────────────────────────────

✗ FA_2026_01_0201.xml — FAIL

XSD: pass | Rules: 128 evaluated, 1 error(s), 1 warning(s)

[FAIL] KSEF-BUS-044 [GOV_MANDATED]

Problem: Wartość netto wiersza (P_11 — kwota netto) nie odpowiada formule: ilość (P_8B) × (cena netto P_9A − rabat P_10 + narzut P_10_Dodatki).

Line net value (P_11 — net amount) does not match the formula: quantity (P_8B) × (unit price P_9A − discount P_10 + surcharge P_10_Dodatki).

Fix:Sprawdź obliczenia na pozycjach faktury — wartość netto (P_11) powinna wynikać z formuły: P_8B × (P_9A − P_10 + P_10_Dodatki), z dokładnością do groszy (tolerancja: 0,02 PLN).

Check the invoice line calculations — the net amount (P_11) should equal P_8B × (P_9A − P_10 + P_10_Dodatki), rounded to grosz (tolerance: 0.02 PLN).

Evidence: NrWierszaFa=2; P_8B=10.00; P_9A=50.00; P_11=0.00

Path:/Faktura/Fa/FaWiersz

Source:Ustawa o VAT Art. 106e ust. 1 pkt 11

[WARN] KSEF-BUS-140 [BEST_PRACTICE]

Problem: Pozycja faktury ma zerową kwotę netto (P_11 — kwota netto = 0) przy stawce opodatkowanej (np. 23%, 8%, 5%). Zerowa kwota netto ze stawką VAT jest podejrzana.

Invoice line has zero net amount (P_11 — net amount = 0) with a taxable rate (e.g. 23%, 8%, 5%). A zero net amount with a VAT rate is suspicious.

Fix:Sprawdź tę pozycję — jeśli kwota netto powinna być większa od zera, popraw ją. Dla pozycji bezpłatnych użyj stawki "zw" (zwolniona) lub "oo" (odwrotne obciążenie).

Check this line — if the net amount should be greater than zero, correct it. For free items, use the "zw" (exempt) or "oo" (reverse charge) rate instead.

Evidence: line 2 P_11=0 with taxable rate P_12='23'

Path:/Faktura/Fa/FaWiersz/P_11

Source:Broszura FA(3), sekcja FaWiersz — P_11

✗ FA_2026_02_0042.xml — FAIL

XSD: pass | Rules: 128 evaluated, 3 error(s), 1 warning(s)

[FAIL] KSEF-BUS-003 [GOV_MANDATED]

Problem: Faktura wystawiona w walucie obcej nie zawiera pola P_14_1W (kwota VAT przeliczona na PLN). Pole to jest wymagane dla każdego koszyka stawki z VAT walutowym.

Foreign currency invoice is missing the P_14_1W field (VAT amount converted to PLN). This field is required for each rate bracket that has foreign-currency VAT.

Fix:Otwórz fakturę walutową i uzupełnij pole P_14_1W kwotą VAT przeliczoną na PLN (wg kursu właściwego dla faktury, zgodnie z art. 31a ustawy o VAT) w sekcji podsumowania.

Open the foreign currency invoice and fill P_14_1W with VAT converted to PLN (using the conversion rate applicable to the invoice per Art. 31a of the VAT Act) in the summary section.

Evidence: KodWaluty=EUR

Path:/Faktura/Fa/P_14_1W

Source:Broszura FA(3), Tabela 26 — P_14_1W..P_14_4W

[FAIL] KSEF-BUS-005 [GOV_MANDATED]

Problem: Faktura walutowa zawiera kwoty VAT w walucie obcej, ale nie ma żadnego przeliczenia VAT na złotówki (pola P_14_*W).

Foreign currency invoice has VAT amounts in the foreign currency, but no PLN VAT conversion (P_14_*W fields) is present.

Source:VAT Act, Art. 106e sec. 11

[FAIL] KSEF-BUS-114 [GOV_MANDATED]

Problem: Faktura walutowa ma wypełnioną kwotę VAT w walucie (P_14_*), ale brak odpowiadającego przeliczenia na PLN (P_14_*W).

Foreign currency invoice has a VAT amount populated but the corresponding PLN conversion is missing.

Source:UoVAT, Art. 31a ust. 1

[WARN] KSEF-BUS-197 [HEURISTIC]

Problem: Faktura ma datę wystawienia (P_1) w weekend (sobota lub niedziela).

Evidence: P_1=2026-02-15 is Sunday

✗ FA_2026_02_0099.xml — FAIL

XSD: pass | Rules: 128 evaluated, 1 error(s), 1 warning(s)

[FAIL] KSEF-BUS-030 [GOV_MANDATED]

Problem: Data wystawienia faktury (P_1) jest ustawiona w przyszłości poza dozwolonym oknem (maks. 30 dni do przodu).

Invoice issue date (P_1) is set in the future beyond the allowed window (max 30 days ahead).

Evidence: P_1=2049-12-31

Source:Art. 106na sec. 1 of the VAT Act (LOGICAL_INFERENCE)

[WARN] KSEF-BUS-168 [HEURISTIC]

Problem: Data wystawienia faktury (P_1) jest ponad 60 dni w przyszłości — prawdopodobnie błędna.

Invoice issue date (P_1) is more than 60 days in the future — likely erroneous.

Evidence: P_1=2049-12-31

✗ FA_2026_02_0187.xml — FAIL

XSD: pass | Rules: 128 evaluated, 2 error(s), 1 warning(s)

[FAIL] KSEF-BUS-006 [GOV_MANDATED]

Problem: Faktura wystawiona w walucie obcej zawiera kwoty VAT, ale brakuje kursu przeliczeniowego (KursWaluty).

Foreign currency invoice has VAT amounts but the exchange rate (KursWaluty) is missing.

Evidence: KodWaluty=EUR

Source:Brochure FA(3), currency section, Art. 106e sec. 11

[WARN] KSEF-BUS-197 [HEURISTIC]

Evidence: P_1=2026-02-28 is Saturday

[FAIL] KSEF-BUS-302 [BATCH_CHECK]

Problem: Guard wykrył regresję daty wystawienia (P_1) w sekwencji numerów faktur.

Guard detected issue date regression in the invoice number sequence.

✓ FA_2026_03_0001.xml — PASS

XSD: pass | Rules: 128 evaluated, 0 error(s), 0 warning(s)

✗ FA_2026_03_0156.xml — FAIL

XSD: fail | Rules: 128 evaluated, 2 error(s), 0 warning(s)

[FAIL] KSEF-BUS-124 [INFERRED]

Problem: Numer NIP 999-999-99-99 ma nieprawidłowy format lub błędną sumę kontrolną.

NIP 999-999-99-99 has an invalid format or incorrect checksum.

Evidence: NIP=999-999-99-99

Source:Broszura FA(3), sekcja Formaty pól, pkt 10

[FAIL] KSEF-BUS-301 [GOV_MANDATED]

Problem: W partii faktur wykryto różne NIP-y sprzedawcy (Podmiot1).

Different seller NIPs (Podmiot1) detected across the invoice batch.

────────────────────────────────────────────────────────

Summary: 1 pass, 5 fail (6 files) in 285ms

Schema: FA(3) 1-0E | Registry: 1.0.0

JSON .\ksef-guard.exe validate --preset recommended --format json Documents\Invoices

{

"validator_version": "1.0.0",

"validation_timestamp": "2026-05-10T13:28:38Z",

"report_schema_version": "1.1",

"preset_name": "recommended",

"structural_pass": false,

"substantive_pass": false,

"rules_evaluated_count": 768,

"online_dependent_unchecked": [],

"triggered_rules": [

{

"rule_id": "KSEF-BUS-003",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-003_MISSING_P_14_1W",

"source_ref": "Broszura FA(3), Tabela 26 — P_14_1W..P_14_4W",

"quote_hash": "b55f2301d2557c1dbfd0de03f01fb9b3…",

"source_url": "https://ksef.podatki.gov.pl/media/…/broszura-fa-3.pdf",

"problem_pl": "Faktura wystawiona w walucie obcej nie zawiera pola P_14_1W…",

"problem_en": "Foreign currency invoice is missing the P_14_1W field…",

"fix_pl": "Otwórz fakturę walutową i uzupełnij pole P_14_1W…",

"fix_en": "Open the foreign currency invoice and fill P_14_1W…",

"quote_pl": "W przypadku, gdy faktura jest wystawiona w walucie obcej…",

"evidence_value": "KodWaluty=EUR",

"evidence_path": "/Faktura/Fa/P_14_1W",

"evidence_line": 41,

"evidence_type": "missing",

"correction_hint": "+ <P_14_1W>",

"legal_basis": [

{

"title_pl": "Kwota podatku wykazywana w złotych",

"title_en": "Tax amounts shown in PLN",

"excerpt_pl": "Kwoty podatku wykazuje się w złotych…",

"source": "Ustawa o VAT, Art. 106e ust. 11"

}

]

{

"rule_id": "KSEF-BUS-005",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-005_NO_PLN_TAX_PRESENTATION",

"evidence_value": "KodWaluty=EUR",

"evidence_path": "/Faktura/Fa/P_14_*W",

"evidence_line": 41,

"evidence_type": "missing",

"correction_hint": "+ <P_14_1W>..<P_14_4W>"

{

"rule_id": "KSEF-BUS-006",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-006_EXCHANGE_RATE_MISSING",

"evidence_value": "KodWaluty=EUR",

"evidence_path": "/Faktura/Fa/FaWiersz/KursWaluty",

"evidence_line": 40,

"evidence_type": "missing",

"correction_hint": "+ <KursWaluty>"

{

"rule_id": "KSEF-BUS-030",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-030_FUTURE_DATE",

"evidence_value": "P_1=2049-12-31",

"evidence_path": "/Faktura/Fa/P_1",

"evidence_line": 24,

"evidence_type": "value",

"correction_hint": "P_1 ≤ 2026-06-09"

{

"rule_id": "KSEF-BUS-044",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-044_LINE_ARITHMETIC_MISMATCH",

"evidence_value": "NrWierszaFa=2; P_8B=10.00; P_9A=50.00; P_11=0.00",

"evidence_path": "/Faktura/Fa/FaWiersz/P_11",

"evidence_line": 44,

"evidence_type": "value",

"correction_hint": "P_11 = 500.00"

{

"rule_id": "KSEF-BUS-114",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "KSEF-BUS-114_MISSING_PLN_CONVERSION|bucket=P_14_1W",

"evidence_value": "KodWaluty=EUR; bucket=P_14_1W",

"evidence_path": "/Faktura/Fa/P_14_*W",

"evidence_line": 41,

"evidence_type": "missing",

"correction_hint": "+ <P_14_xW>"

{

"rule_id": "KSEF-BUS-124",

"result": "FAIL",

"severity": "error",

"classification_tag": "INFERRED",

"reason_code": "KSEF-BUS-124_INVALID_NIP_FORMAT: 999-999-99-99",

"evidence_value": "NIP=999-999-99-99",

"evidence_path": "/Faktura/Podmiot1/DaneIdentyfikacyjne/NIP",

"evidence_line": 14,

"evidence_type": "value",

"correction_hint": "NIP: [0-9]{10}"

{

"rule_id": "KSEF-BUS-140",

"result": "FAIL",

"severity": "warning",

"classification_tag": "BEST_PRACTICE",

"reason_code": "KSEF-BUS-140_ZERO_VALUE_LINE",

"evidence_value": "line 2 P_11=0 with taxable rate P_12='23'",

"evidence_path": "/Faktura/Fa/FaWiersz/P_11",

"evidence_line": 44,

"evidence_type": "value",

"correction_hint": "P_11 > 0 ?"

{

"rule_id": "KSEF-BUS-168",

"result": "FAIL",

"severity": "warning",

"classification_tag": "HEURISTIC",

"reason_code": "KSEF-BUS-168_FAR_FUTURE_DATE",

"evidence_value": "P_1=2049-12-31",

"evidence_path": "/Faktura/Fa/P_1",

"evidence_line": 24,

"evidence_type": "value",

"correction_hint": "P_1 ≤ 2026-07-09"

{

"rule_id": "KSEF-BUS-197",

"result": "FAIL",

"severity": "warning",

"classification_tag": "HEURISTIC",

"reason_code": "KSEF-BUS-197_WEEKEND_ISSUE: P_1=2026-02-15 is Sunday",

"evidence_value": "P_1=2026-02-15 is Sunday",

"evidence_path": "/Faktura/Fa/P_1",

"evidence_line": 24,

"evidence_type": "value",

"correction_hint": "P_1 → weekday"

{

"rule_id": "KSEF-BUS-197",

"result": "FAIL",

"severity": "warning",

"classification_tag": "HEURISTIC",

"reason_code": "KSEF-BUS-197_WEEKEND_ISSUE: P_1=2026-02-28 is Saturday",

"evidence_value": "P_1=2026-02-28 is Saturday",

"evidence_path": "/Faktura/Fa/P_1",

"evidence_line": 24,

"evidence_type": "value",

"correction_hint": "P_1 → weekday"

{

"rule_id": "KSEF-BUS-301",

"result": "FAIL",

"severity": "error",

"classification_tag": "GOV_MANDATED",

"reason_code": "NIP_MISMATCH",

"evidence_value": "NIP='999-999-99-99' differs from majority '1111111111'",

"evidence_path": "/Faktura/Podmiot1/DaneIdentyfikacyjne/NIP"

{

"rule_id": "KSEF-BUS-302",

"result": "FAIL",

"severity": "error",

"classification_tag": "BATCH_CHECK",

"reason_code": "DATE_REGRESSION",

"evidence_value": "P_1 date regression in sequence 'FV/2026/02/'",

"evidence_path": "/Faktura/Fa/P_1"

}

"results": [

{

"filename": "FA_2026_01_0201.xml",

"structural_pass": true,

"substantive_pass": false,

"error_count": 1,

"warning_count": 1,

"xsd_error_count": 0

{

"filename": "FA_2026_02_0042.xml",

"structural_pass": true,

"substantive_pass": false,

"error_count": 3,

"warning_count": 1,

"xsd_error_count": 0

{

"filename": "FA_2026_02_0099.xml",

"structural_pass": true,

"substantive_pass": false,

"error_count": 1,

"warning_count": 1,

"xsd_error_count": 0

{

"filename": "FA_2026_02_0187.xml",

"structural_pass": true,

"substantive_pass": false,

"error_count": 2,

"warning_count": 1,

"xsd_error_count": 0

{

"filename": "FA_2026_03_0001.xml",

"structural_pass": true,

"substantive_pass": true,

"error_count": 0,

"warning_count": 0,

"xsd_error_count": 0

{

"filename": "FA_2026_03_0156.xml",

"structural_pass": false,

"substantive_pass": false,

"error_count": 2,

"warning_count": 0,

"xsd_error_count": 1

}

]

}

CSV .\ksef-guard.exe validate --preset recommended --format csv Documents\Invoices

file_name	file_status	risk_score	violation_type	code	severity	classification	problem_pl	problem_en	fix_pl	fix_en	evidence_xpath	evidence_value	source_ref	source_url	quote_pl	quote_en	page_number
FA_2026_01_0201.xml	FAIL	25	RULE	KSEF-BUS-044	error	GOV_MANDATED	Wartość netto wiersza (P_11 — kwota netto) nie odpowiada formule…	Line net value (P_11 — net amount) does not match the formula…	Sprawdź obliczenia na pozycjach faktury — wartość netto (P_11)…	Check the invoice line calculations — the net amount (P_11)…	/Faktura/Fa/FaWiersz	NrWierszaFa=2; P_8B=10.00; P_9A=50.00; P_11=0.00	Ustawa o VAT Art. 106e ust. 1 pkt 11	https://isap.sejm.gov.pl/…WDU20250000775	11) wartość dostarczonych towarów lub wykonanych usług…	11) Value of goods delivered or services provided…	124
FA_2026_01_0201.xml	FAIL	25	RULE	KSEF-BUS-140	warning	BEST_PRACTICE	Pozycja faktury ma zerową kwotę netto (P_11=0)…	Invoice line has zero net amount (P_11=0)…	Sprawdź tę pozycję — jeśli kwota netto…	Check this line — if the net amount…	/Faktura/Fa/FaWiersz/P_11	line 2 P_11=0 with taxable rate P_12='23'	Broszura FA(3), sekcja FaWiersz — P_11	https://ksef.podatki.gov.pl/…pdf#page=92	Wiersze faktury z zerową kwotą netto…	Invoice lines with zero net amount…	92
FA_2026_02_0042.xml	FAIL	65	RULE	KSEF-BUS-003	error	GOV_MANDATED	Faktura wystawiona w walucie obcej nie zawiera pola P_14_1W…	Foreign currency invoice is missing the P_14_1W…	Otwórz fakturę walutową i uzupełnij pole P_14_1W…	Open the foreign currency invoice and fill P_14_1W…	/Faktura/Fa/P_14_1W	KodWaluty=EUR	Broszura FA(3), Tabela 26 — P_14_1W..P_14_4W	https://ksef.podatki.gov.pl/…pdf#page=47	W przypadku, gdy faktura jest wystawiona w walucie obcej…	If the invoice is issued in a foreign currency…	47
FA_2026_02_0042.xml	FAIL	65	RULE	KSEF-BUS-005	error	GOV_MANDATED	Faktura walutowa zawiera kwoty VAT w walucie…	Foreign currency invoice has VAT amounts…	Otwórz fakturę walutową i dodaj przeliczenie…	Open the foreign currency invoice and add…	/Faktura/Fa/P_14_*W	KodWaluty=EUR	VAT Act, Art. 106e sec. 11	https://isap.sejm.gov.pl/…	11. Kwoty podatku wykazuje się w złotych…	11. Tax amounts shall be shown in Polish zlotys…	126
FA_2026_02_0042.xml	FAIL	65	RULE	KSEF-BUS-114	error	GOV_MANDATED	Faktura walutowa ma niezerowy VAT w koszyku stawki…	Foreign currency invoice has a non-zero VAT…	Uzupełnij brakujące pole P_14_xW przeliczeniem…	Fill in the missing P_14_xW field with the PLN…	/Faktura/Fa/P_14_*W	KodWaluty=EUR; bucket=P_14_1W	UoVAT, Art. 31a; FA(3) P_14_xW	https://isap.sejm.gov.pl/…	Dla waluty obcej każde pole P_14_xW…	For foreign currency invoices…	43
FA_2026_02_0042.xml	FAIL	65	RULE	KSEF-BUS-197	warning	HEURISTIC	Faktura ma datę wystawienia (P_1) w weekend…	Invoice has issue date (P_1) on a weekend…	Sprawdź datę wystawienia faktury…	Check the invoice issue date…	/Faktura/Fa/P_1	KSEF-BUS-197_WEEKEND_ISSUE: P_1=2026-02-15 is Sunday	KSeF Guard heuristic (weekend invoice issuance…	https://ksef.podatki.gov.pl/…pdf#page=43	Wystawienie faktury w weekend…	Invoice issuance on weekends…	43
FA_2026_02_0099.xml	FAIL	25	RULE	KSEF-BUS-030	error	GOV_MANDATED	Data wystawienia (P_1) jest w przyszłości…	Invoice issue date (P_1) is set in the future…	Sprawdź datę wystawienia — maks. 30 dni…	Check the issue date — max 30 days ahead…	/Faktura/Fa/P_1	P_1=2049-12-31	Art. 106na ust. 1 Ustawy o VAT (LOGICAL_INFERENCE)	https://ksef.podatki.gov.pl/…pdf#page=43	Faktury mogą być wystawiane…	Invoices may be issued no earlier…	43
FA_2026_02_0099.xml	FAIL	25	RULE	KSEF-BUS-168	warning	HEURISTIC	Data wystawienia (P_1) jest ponad 60 dni…	Invoice issue date (P_1) is more than 60 days…	Sprawdź rok i dzień daty wystawienia…	Verify the year and day are correct…	/Faktura/Fa/P_1	P_1=2049-12-31	UoVAT, Art. 106i ust. 7; Broszura FA(3) P_1, P_6	https://isap.sejm.gov.pl/…	Faktura może być wystawiona…	An invoice may be issued…	130
FA_2026_02_0187.xml	FAIL	25	RULE	KSEF-BUS-006	error	GOV_MANDATED	Faktura walutowa ma kwoty VAT, ale brak kursu…	Foreign currency invoice has VAT but exchange…	Uzupełnij kurs waluty (KursWaluty)…	Fill in the exchange rate (KursWaluty)…	/Faktura/Fa/FaWiersz/KursWaluty	KodWaluty=EUR	Brochure FA(3), currency section, Art. 106e sec. 11	https://ksef.podatki.gov.pl/…pdf#page=99	Kurs waluty stosowany do obliczenia…	The exchange rate used to…	99
FA_2026_02_0187.xml	FAIL	25	RULE	KSEF-BUS-197	warning	HEURISTIC	Faktura ma datę wystawienia (P_1) w weekend…	Invoice has issue date (P_1) on a weekend…	Sprawdź datę wystawienia faktury…	Check the invoice issue date…	/Faktura/Fa/P_1	KSEF-BUS-197_WEEKEND_ISSUE: P_1=2026-02-28 is Saturday	KSeF Guard heuristic (weekend invoice issuance…	https://ksef.podatki.gov.pl/…pdf#page=43	Wystawienie faktury w weekend…	Invoice issuance on weekends…	43
FA_2026_02_0187.xml	FAIL	25	RULE	KSEF-BUS-302	error	BATCH_CHECK	Data faktury (P_1) cofa się w sekwencji…	Invoice date (P_1) regresses within a sequential…	Sprawdź daty faktur w sekwencji numerów…	Check invoice dates in the sequential series…	/Faktura/Fa/P_1	P_2='FV/2026/02/0187' regresses from…	Art. 106e ust. 1 pkt 1 ustawy o VAT — data wystawienia	https://isap.sejm.gov.pl/…	Daty faktur (P_1) w ciągu numerów…	Invoice dates (P_1) must be…	43
FA_2026_03_0001.xml	PASS	0	-	-	-	-
FA_2026_03_0156.xml	FAIL	40	XSD	FA3-XSD-E001	error	-	NIP: tylko 10 cyfr (bez myślników)	NIP: 10 digits only (no dashes)	Wprowadź poprawny 10-cyfrowy NIP…	Enter a valid 10-digit NIP number…	{…}NIP	999-999-99-99	Schemat XSD FA(3), element: NIP
FA_2026_03_0156.xml	FAIL	40	RULE	KSEF-BUS-124	error	INFERRED	NIP 999-999-99-99 ma nieprawidłowy format…	NIP 999-999-99-99 has an invalid format…	Sprawdź numer NIP — 10 cyfr bez myślników…	Verify the NIP — 10 digits without dashes…	/Faktura/Podmiot1/…/NIP	NIP=999-999-99-99	Broszura FA(3), Page 6 — Formaty pol…	https://ksef.podatki.gov.pl/…pdf#page=6	Numer NIP powinien składać się…	NIP number should consist of…	6
FA_2026_03_0156.xml	FAIL	40	RULE	KSEF-BUS-301	error	GOV_MANDATED	NIP sprzedawcy różni się od NIP dominującego…	Seller NIP differs from the batch majority…	Sprawdź NIP sprzedawcy (Podmiot1/NIP)…	Check seller NIP (Podmiot1/NIP)…	/Faktura/Podmiot1/…/NIP	Seller NIP='999-999-99-99' differs from batch majority…	KSeF session single-taxpayer requirement	https://isap.sejm.gov.pl/…WDU20250000775	Wszystkie faktury w sesji KSeF…	All invoices submitted in a…	124

15 rows · 18 columns · UTF-8 BOM · Excel-compatible

KSeF Guard vs the Competition

107 rules beyond KSeF — 55 legal, 52 best-practice and security.

Free tier · 128 rules · Offline

KSeF Guard vs the Competition
Feature	KSeF Guard	ksefuj.to	Sorgera	CFOall	KSeFka
Privacy & Security
Data privacy	Validation runs offline — invoice data stays local	Browser-side processing	Cloud upload required	Cloud upload required	Offline desktop app
Offline / air-gapped	Yes — validation runs offline. License, payments, updates may connect.	Browser-based, offline after load	No — cloud required	No — cloud SaaS	Yes — runs offline
No telemetry	Verified — no analytics, no tracking	Amplitude + Vercel (anonymized)	Cookies + analytics	Unknown	—
Validation Depth
Catches beyond KSeF	107 rules beyond KSeF (55 legal)↗	—	—	—	—
Validation rules beyond XSD	128 with source-backed evidence↗	44 semantic rules, cites Art. 31a	XSD-focused, no citations	Undisclosed, no citations	XSD validation only
KSeF API conformance tested	256 invoices, 0 false negatives (conformance v9)↗	—	—	—	—
Legal source provenance	SHA-256 verified quotes from VAT Act↗	Cites Art. 31a (no full chain)	—	—	—
XSD schema validation	Full libxml2	Yes	Yes	Yes	Yes
Smart fix hints	Bilingual problem + fix per rule	XPath + fix hints	Line-level highlighting	Suggestions + live fixes	XSD error messages
Workflow & Reporting
Batch processing	5,000 files/day (Standard), unlimited (Pro)	Multiple files	Up to 50 files (paid)	Bulk, up to 1,000/mo	Single file
PDF audit report	White-label PDF with legal chain	No	No	No	No
Export formats	TXT, CSV, JSON, PDF	None	None	XLS, XML, CSV	None
Rule configuration	Per-rule enable/disable, YAML profiles	No	No	Limited	No
CLI for CI/CD	Exit codes 0–130, JSON output	Yes (npm package)	No	No	No
Bilingual interface	Polish + English	Polish, English, Ukrainian	English only	Polish + English	Polish only
Price & Access
Entry price	Free (10 files/day)	Free	Free (10/day), €15/1k credits	120 PLN/mo (~€27)	Free
Unlimited usage	€89/month (Pro)	N/A	Pay-per-use credits	No unlimited (max 1,000/mo)	N/A
Platform	Windows desktop + CLI (Linux CLI)	Web browser	Web browser	Web / cloud	Desktop (Windows, macOS, Linux)
Open source	No — SHA-256 verified rule provenance	Apache 2.0	No	No	No
Product status	Available	Released	Released	Released	Released

✓ yes · ✗ no · — unknown or not tested

Conformance v9 methodology: 256 test invoices submitted to KSeF test API 2.3.0 on 2026-05-25. Results: 0 false negatives, 98 false-positive fixtures (94 active rules, plus 4 from inactive rules). Including 12 additional rules verified by static analysis and batch testing, KSeF Guard validated 107 rules beyond KSeF API, of which 55 are legal requirements.

Comparison based on publicly available information as of May 2026. We strive for accuracy — contact [email protected] if any claim needs correction.

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Frequently Asked Questions

What is KSeF and do I need this tool?

KSeF (Krajowy System e-Faktur) is Poland's mandatory structured e-invoicing system. If your business issues invoices in Poland, they must conform to the FA(3) XML schema. KSeF Guard validates your invoices locally before submission.

Is my invoice data sent anywhere?

No. KSeF Guard validates invoices on your local machine. Validation runs offline. License activation, payments, and automatic updates may connect — but invoice content is never transmitted.

How does KSeF Guard compare to cloud alternatives?

KSeF Guard validates offline — invoice data stays on your machine. It checks validation rules with source-backed evidence. Starts free, with paid tiers for batch validation and advanced exports. See the comparison page for a detailed feature breakdown.

How many rules does KSeF Guard check?

128 active validation rules across six classifications: GOV_MANDATED (legally required checks based on the VAT Act), BEST_PRACTICE (recommended validations from the Ministry of Finance brochure), HEURISTIC (smart anomaly detection like weekend issuance), SECURITY (data integrity checks), BATCH_CHECK (cross-invoice consistency validations), and INFERRED (rules derived from schema structure and domain logic).

What's the difference between Standard and Pro?

Standard offers 5,000 files/day, 3 activations, GUI export and PDF, and rule configuration. Pro adds unlimited quota, 10 activations, YAML configuration, white-label PDF, export presets, and CI/CD documentation.

Can I cancel my subscription?

Yes. Your subscription remains active until the end of the current billing period. There is no automatic renewal after cancellation.

How does VAT work?

Prices are listed as net. VAT is automatically applied by DodoPayments (Merchant of Record) based on your location.

What is white-label PDF?

White-label PDF is a validation report featuring your own logo and company header instead of KSeF Guard branding. You can share it with clients or auditors as a branded document.

Does passing KSeF Guard guarantee KSeF will accept my invoice?

No. KSeF Guard validates against the FA(3) schema and 128 legal and best-practice rules, and it intentionally catches issues the KSeF API does not — in conformance v9 it had 0 false negatives. But final acceptance is decided by KSeF, and factors outside the file (your authorizations, permissions, or session state) can still cause a rejection. A PASS means the invoice is structurally and substantively sound, not a guarantee of acceptance.

Does KSeF Guard support FA(2), or only FA(3)?

KSeF Guard targets the current FA(3) structured-invoice schema — the format mandated for KSeF. Older FA(2) files are not validated; convert them to FA(3) first. See our FA(2)-to-FA(3) migration guide for the field-level differences.

Which operating systems are supported?

KSeF Guard's desktop application and CLI are distributed for Windows 10 and later (64-bit). macOS and Linux desktop builds are not offered at this time.