🇵🇱 Poland E-Invoicing — KSeF System

Poland is implementing one of Europe's most ambitious e-invoicing systems: the Krajowy System e-Faktur (KSeF), a centralized national platform for issuing, receiving, and storing structured electronic invoices. After an initial postponement in 2024, KSeF will become mandatory for all B2B transactions starting in February 2026, fundamentally changing how invoices are exchanged in the Polish economy.

This comprehensive guide covers the KSeF platform, the FA(2) invoice format, the rollout timeline, and what businesses operating in Poland need to do to prepare for compliance.

Timeline of E-Invoicing in Poland

Understanding the KSeF Platform

KSeF is a centralized government platform operated by the Polish Ministry of Finance. Unlike decentralized e-invoicing networks like Peppol, KSeF acts as a central repository where all invoices are submitted, validated, stored, and made available to recipients. This architecture gives the tax authority real-time visibility into all B2B transactions.

How KSeF Works

1. Invoice Creation: The seller creates an invoice in FA(2) XML format using their ERP or accounting software.
2. Submission to KSeF: The invoice is submitted to the KSeF platform via API. KSeF validates the invoice against the FA(2) schema.
3. KSeF Number Assigned: Upon successful validation, KSeF assigns a unique identification number and timestamp. This is the official moment the invoice is considered issued.
4. Recipient Access: The buyer can retrieve the invoice from KSeF using the unique number or through their KSeF account. The platform serves as the authoritative source.
5. Storage: KSeF stores invoices for 10 years, fulfilling archiving obligations for both parties.

Who Is Affected?

B2B (Business-to-Business)

All VAT-registered businesses conducting B2B transactions in Poland will be required to use KSeF. This includes domestic transactions as well as invoices issued by Polish entities to foreign businesses (though the recipient is not required to use KSeF if they are outside Poland). The mandate covers sales invoices, corrective invoices, and advance payment invoices.

B2G (Business-to-Government)

Public sector suppliers are included in the KSeF mandate. Invoices to government entities will also need to flow through the centralized platform, aligning B2G invoicing with the same system used for B2B.

B2C (Business-to-Consumer)

Consumer invoices are exempt from the KSeF mandate. Businesses may continue to issue B2C invoices in any format, including paper and PDF. However, businesses may voluntarily choose to issue B2C invoices through KSeF.

Foreign Businesses

Foreign companies registered for VAT in Poland and issuing invoices for Polish domestic transactions will need to comply with KSeF. Companies without a Polish VAT registration are not directly affected but should monitor developments as their Polish business partners will require KSeF-compliant invoices.

The FA(2) Invoice Format

FA(2) is the structured XML format required for invoices submitted through KSeF. It is a Polish-specific schema developed by the Ministry of Finance, distinct from European standards like Peppol BIS 3.0 or XRechnung. The format includes:

• Seller and buyer identification (NIP tax numbers)
• Invoice header with dates, currency, and payment terms
• Detailed line items with quantities, prices, and VAT rates
• Polish-specific tax classifications and split payment markers
• Support for corrective invoices and advance payment invoices

While FA(2) is specific to Poland, businesses operating across Europe should consider how their invoicing systems can handle multiple formats. Tools that support conversion between formats can simplify compliance across jurisdictions.

How to Prepare for KSeF Compliance

1. Assess your current systems: Determine whether your ERP or accounting software supports KSeF integration and FA(2) format generation. Contact your software vendor about their KSeF readiness roadmap.
2. Start with voluntary adoption: KSeF is already available on a voluntary basis. Testing your systems now gives you time to identify and resolve issues before the mandate takes effect.
3. Set up KSeF authentication: Businesses need to register and configure API access to KSeF, including digital certificates or trusted profile authentication for authorized personnel.
4. Update internal processes: Invoice approval workflows, archiving procedures, and reconciliation processes will all change with KSeF. Plan for staff training and process redesign.
5. Plan for corrective invoices: Under KSeF, corrective invoices follow specific rules. Ensure your team understands the new correction workflow within the platform.

Frequently Asked Questions

Poland in the European E-Invoicing Landscape

Poland's centralized KSeF approach differs from the decentralized models used in countries like Germany and the Netherlands, which rely more heavily on the Peppol network. It shares more similarities with Italy's SDI system, where a central government platform processes all invoices.

Explore e-invoicing requirements across Europe:

• Spain E-Invoicing — Ley Crea y Crece and the Facturae standard
• France E-Invoicing — Chorus Pro and the PPF platform
• Denmark E-Invoicing — Pioneer in B2G with NemHandel
• Belgium E-Invoicing — Peppol-based B2G mandate

For format-specific guides, see: Peppol BIS 3.0 | XRechnung | ZUGFeRD.