`FA3-NIP-FORMAT`

KSeF FA(3) · validation rule

KSeF FA(3)Error

A NIP (Polish tax id) in Podmiot1/Podmiot2/Podmiot3 does not match the schema pattern: exactly 10 digits, no 'PL' prefix, no dashes or spaces. The sender must correct DaneIdentyfikacyjne/NIP.

Field: seller.tax_registration_id / buyer.tax_registration_id (FA3 DaneIdentyfikacyjne/NIP)
Rule set: KSeF FA(3)
Rule-set version: KSeF FA(3) schema 1-0E XSD · in force since 2026-09-07
KSeF FA(2) schema 1-0E XSD · in force since 2026-09-07 · Rule-set changelog
Who has to fix it: The sender

This is a property of the file you received, so it cannot be corrected on your side without changing the document — ask the supplier to reissue it.

Check your own invoice

Drop the file that failed. We parse it, run the official rule sets against it and list every finding with a fix — 20 invoices per day, no key, nothing stored.

Open the live demo

Same explanation over the API: GET /v1/rules/FA3-NIP-FORMAT?lang=en