KSEF-004:Currency code invalid
Currency must be a valid ISO 4217 code. Use PLN for domestic invoices.
Engine Classification
Business data required · Explicit input workflow · No assumptions made
Required input: Currency Code
What is KSEF-004?
KSEF-004 is a fatal validation rule defined in the KSeF specification (POL national rules). It checks whether currency code invalid.
When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.
Why This Error Matters
KSEF-004 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.
Validator Behavior
- ·Causes invoice rejection
- ·Error returned: KSEF-004
- ·Specification: KSeF
How to Fix It
Technical Reference
Code Example
<KodWaluty>PLN</KodWaluty>Common Causes
- ·Invalid currency code format
- ·Using currency symbol instead of code
- ·Typo in currency code
Seeing this in production? The API handles KSEF-004 automatically. See the fix response →
Frequently Asked Questions
Currency must be a valid ISO 4217 code. Use PLN for domestic invoices.
Use correct ISO 4217 currency code. Invoice Navigator detects this error and prompts for the required business data before applying a safe fix.
Yes, KSEF-004 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.
KSEF-004 requires specific business data to resolve. Invoice Navigator detects the error and guides you through providing the needed information, then applies the fix with full audit documentation.
Related Content
Last updated: 3 March 2026
Resolve KSEF-004 with Guided Input
The compliance engine detects this error and prompts for the required business data before applying a safe, auditable fix.