Understanding FA(3) for eInvoicing in Poland
This article describes the FA(3) format, as well as why it came to be – and how to start using it in Continia Document Capture and Continia eDocuments.
Definitions
FA(3) is a standardized eInvoicing format developed by the Polish Ministry of Finance. The goal of this format is to ensure consistency and interoperability across industries and enterprise resource planning (ERP) systems. FA(3) is based on XML, and it's the mandatory structured invoice format used by the Krajowy System e‑Faktur (KSeF) platform.
Why FA(3)?
The Polish Ministry of Finance created FA(3) specifically to support the KSeF's requirements for auditability and automated validation.
The schema was developed with input from tax experts, accountants, and software vendors to meet the KSeF’s operational needs. Among other improvements over the format it replaces, FA(2), the FA(3) format:
- Supports structured attachments and wider date ranges
- Accepts more types of bank accounts.
- Adds identifiers for VAT groups.
Legislation in Poland
Since 1 February, 2026, FA(3) is the required format for all B2G eInvoicing in Poland, as well as for B2B eInvoicing of large taxpayers – that is, those with an annual turnover of at least 200 million PLN. From 1 April 2026, this mandate applies to all taxpayers in the country.
For more information, see Managing electronic documents in Poland.
To start using FA(3)
Starting with Document Capture version 27 Service Pack 3, you can receive FA(3) purchase documents through the KSeF integration provided by the Polish localization from IT.integro. For more information, see Setting up the FA(3) format in eDocuments.