Poland?s FA3 Schema & KSeF E-Invoicing Mandate | 2026 Compliance Guide

Poland is advancing digital tax administration with the National e-Invoicing System (KSeF), which will soon mandate e-invoicing for all businesses. Central to this initiative is the FA3 data schema, a new standardized XML format designed to replace the current FA2 schema. The FA3 schema aims to enhance transparency, reduce tax fraud, and streamline business transactions by ensuring all e-invoices are machine-readable and interoperable across systems.

Background on E-Invoicing in Poland

Poland?s e-invoicing reform aligns with broader European efforts to close the VAT gap?the difference between expected and actual VAT revenue. KSeF was introduced voluntarily in January 2022 and is already mandatory for business-to-government (B2G) transactions since 2019. The system will extend to business-to-business (B2B) transactions in 2026, following approval from the European Commission to derogate from the VAT Directive and implement a Continuous Transaction Controls (CTC) model for real-time tax oversight.

Timeline for Mandatory E-Invoicing

The rollout of mandatory e-invoicing is phased to accommodate different business sizes:

• February 1, 2026: Mandatory for taxpayers with annual sales exceeding PLN 200 million (approx. EUR 46 million) in the previous year.
• April 1, 2026: Mandatory for all other VAT taxpayers.

The Ministry of Finance has outlined a roadmap that includes API testing in September 2025 and a test version of the KSeF 2.0 Taxpayer Application in November 2025.

What is the FA3 Data Schema?

The FA3 schema defines the logical structure, format, and content of e-invoices submitted through KSeF, replacing the FA2 schema used for voluntary e-invoicing. FA3 standardizes invoice data in a machine-readable XML format, facilitating automated processing, tax compliance, and system interoperability. The draft FA3 schema was released on May 8, 2025, and the official version is expected in June 2025. Its development incorporated feedback from businesses, accountants, and IT providers to better align with market needs.

Key Differences Between FA3 and FA2

These changes make FA3 more flexible and aligned with modern invoicing practices.

Key Features of FA3

• Structured Attachments: Invoices can now include supporting documents like contracts or delivery proofs, streamlining B2B workflows.
• Enhanced Payment Information: New fields for payment links and methods support online transactions and clarify payment status.
• Expanded VAT Rates: Additional codes ensure more accurate tax reporting, especially for non-taxable transactions.
• Employee Expense Tracking: New entity roles simplify identification of employee-related expenses.
• Correction Invoice Limits: A 50,000-line cap on corrections prevents system overload and ensures efficient processing.
• Flexible Payment Deadlines: Payment terms can be tied to events, offering greater adaptability for businesses.

These features were developed based on stakeholder feedback to address diverse business needs.

Implications for Businesses

Transitioning to FA3 and mandatory e-invoicing requires significant preparation:

• Update Invoicing Systems: Ensure software supports FA3 and integrates with KSeF, either directly or through intermediaries.
• Train Staff: Educate employees on new processes and compliance requirements.
• Review Compliance Procedures: Align accounting and tax practices with FA3 standards.
• Engage Specialists: Consult experts for technical and legal guidance.
• Test Integrations: Participate in API testing from September 30, 2025, to ensure readiness.

Conclusion

The transition to the FA3 data schema is a significant step in Poland's efforts to modernize tax administration. For businesses, this means adapting to new standards to maintain compliance and avoid penalties. Contact us for expert guidance.