A Complete Guide to Poland’s FA3 Data Schema for E-Invoices

Poland’s National e-Invoicing System (KSeF) mandates e-invoicing for all businesses starting February 2026, replacing the FA2 schema with FA3 to enhance transparency, reduce tax fraud, and ensure machine-readable, interoperable invoice data.

FA3 schema introduces new features such as structured attachments, enhanced payment information, expanded VAT rate codes, employee expense tracking, and flexible payment deadlines, aligning invoicing practices with modern business needs and improving tax reporting accuracy.

The phased rollout targets large taxpayers from February 2026, followed by all other VAT payers in April 2026, supported by API testing starting September 2025 and a KSeF 2.0 test app in November 2025.

Businesses must update invoicing software, train staff, review compliance processes, and engage experts to prepare for FA3 adoption, ensuring smooth integration with KSeF and adherence to new legal and technical requirements.