CURRENCY_RATE_UNVERIFIABLE: KursWaluty cannot be verified

StandardKSeF FA(3), Polish national e-invoicing systemSeverityWarning: the invoice is accepted but should be correctedSyntaxFA(3) XMLApplies toStructured invoices (FA(3) schema) submitted to the Polish KSeF. XSD codes come from the schema, semantic codes from the Ministry of Finance information sheet; KSeF rejects invoices that fail an error-level rule.

Official rule text

[CURRENCY_RATE_UNVERIFIABLE] KursWaluty cannot be verified — NBP rate unavailable or outside the valid date window (Art. 31a ustawy o VAT)

Why this error occurs

KSeF checks the FA(3) XML in two stages: XSD schema (structure, element order, data types, patterns such as NIP or dates) and semantic rules from the Ministry of Finance information sheet (consistency of amounts, annotations P_16 to P_23, roles of Podmiot2/Podmiot3, bank account formats, currency rates).

How to fix it

Fix the element named in the message. For XSD errors compare the element order and value pattern with the FA(3) schema; for semantic errors apply the cause and fix hints listed on this page. Re-validate before submitting to KSeF: a rejected invoice has no KSeF number and is not issued.

What the validator checks

Check levelsemantic / business_logic

Typical causes

NBP API unavailable or rate-limited during validation
Rate data provided is from a date too far from the invoice date
Network error during rate lookup

Check your invoice

Drop your XML or PDF on the validator and every failed rule is linked to its page here. Free, no account, the file is not stored.

Check your invoice →

Same check via API:

curl -F file=@invoice.xml https://einvoicechecker.com/v1/validate

Related rules

CURRENCY_RATE_MISMATCH KursWaluty does not match the NBP Table A mid-rate for the reference date (Art
FOREIGN_CURRENCY_TAX_PLN Foreign currency invoice with tax amounts should include PLN conversions in P_14_*W…
KURS_WALUTY_Z_PLACEMENT KursWalutyZ at Fa level is ONLY valid for advance invoices (RodzajFaktury = ZAL or…
NEGATIVE_QUANTITY_NOT_ALLOWED Negative quantities (P_8B) are only allowed in corrective invoices (RodzajFaktury =…
NIP_IN_WRONG_FIELD Polish NIP detected in NrVatUE field - must be in NIP field for purchaser KSeF access…
OO_RATE_FOREIGN_BUYER P_12 = 'oo' is for domestic reverse charge only
P12_ENUMERATION P_12 must be one of
SELF_BILLING_PODMIOT3_CONFLICT Self-billing (P_17 = '1')

Frequently asked questions

What does CURRENCY_RATE_UNVERIFIABLE mean?

CURRENCY_RATE_UNVERIFIABLE is a ksef fa(3) rule: KursWaluty cannot be verified — NBP rate unavailable or outside the valid date window (Art. 31a ustawy o VAT)

Will my invoice be rejected because of CURRENCY_RATE_UNVERIFIABLE?

No. CURRENCY_RATE_UNVERIFIABLE is a warning: the invoice is accepted but the recipient sees the notice. Fix it anyway, warnings often become errors in later rule versions.

Which formats does CURRENCY_RATE_UNVERIFIABLE apply to?

Structured invoices (FA(3) schema) submitted to the Polish KSeF. XSD codes come from the schema, semantic codes from the Ministry of Finance information sheet; KSeF rejects invoices that fail an error-level rule. Syntax: FA3.

Source: KSeF FA(3) schema 1-0E + semantic rules (@ksefuj/validator 0.4). Catalogue generated from the official rule sets on 2026-10-15.

CURRENCY_RATE_UNVERIFIABLE: KursWaluty cannot be verified — NBP rate unavailable or outside the valid date window (Art