Overview
In KSeF, a correction invoice (faktura korygująca) is a new FA(3) document that references the invoice it corrects through fields such as NrKSeFFaKorygowanej (the KSeF number of the corrected invoice) and PrzyczynaKorekty (the reason for the correction). You do not edit the original invoice; you send a correcting document that points back to it. Whether a correction is required, and how the VAT difference is settled, is a tax decision for your accountant — the FA(3) format only describes the structure.
Where the correction fields live
KSeF (Krajowy System e-Faktur) is Poland's national e-invoicing platform operated by the Ministry of Finance (Ministerstwo Finansów). In the FA(3) schema the correction information sits in the invoice header alongside the normal invoice data. The main elements include the KSeF number of the corrected invoice (NrKSeFFaKorygowanej), the reason for the correction (PrzyczynaKorekty) and the correction type (TypKorekty), which describes the effect of the correction in VAT records.
A correction is a new document, not an edit
Because KSeF stores invoices immutably, you cannot silently rewrite an already-accepted invoice. A correction is a separate FA(3) invoice that carries the corrected values and points back to the original. Once submitted, it goes through the same status cycle as any other invoice — submitted, then accepted (with its own UPO) or rejected.
What the format does not decide
The FA(3) schema tells you which fields exist and how they are typed. It does not tell you whether a given situation requires a correction, which values to change, or how the tax difference is recognised. Those are VAT decisions that depend on Polish tax law and the specific transaction, so they belong with a qualified accountant — not with a schema reference or an integration.
How Notaly handles corrections
A KSeF API such as Notaly's sends a correction the same way as any invoice: you provide the corrected data and the reference to the original, and the API generates the FA(3) XML, validates it against the official XSD and submits it to KSeF, returning the status and UPO. The tax logic stays yours; the format and transport are handled for you.
Disclaimer
Notaly is not a tax, accounting or legal advisor. This article is general information, not tax advice, and may be outdated. You are responsible for your own VAT compliance; confirm with a qualified accountant where required.
Sources
Source: crd.gov.pl