Poland’s B2B e-Invoicing mandate: Get ready now for February 2026

With the KSeF 2.0 manual out, testing scheduled for November, and February 2026 just months away, now is the time to have the right e-invoicing compliance platform

With the mandatory launch of Poland’s e-invoicing system, Krajowy System e-Faktur (KSeF), just a few months away, the time to prepare is now. The Polish Ministry of Finance is actively promoting the system and has recently published its new KSeF 2.0 Manual, providing comprehensive guidance for businesses. For large taxpayers, the deadline of February 1, 2026, is firm, and the need to test and adapt processes is urgent.

This update covers the latest details on the mandate, what’s required for compliance, and how businesses can move from preparation to full readiness.

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The KSeF mandate: A quick overview

The KSeF system is a centralized platform for issuing, receiving, and storing B2B invoices in Poland. The goal is to digitize tax reporting and combat fraud. While the initial deadline was postponed, the phased rollout is now confirmed:

• February 1, 2026: Mandatory for large taxpayers (with turnover exceeding PLN 200 million).
• April 1, 2026: Mandatory for all other businesses.
• January 1, 2027: Micro-businesses formally join the system.

This phased approach gives larger organizations (which typically have more complex systems) time to integrate, while providing a longer runway for small and micro-businesses.

Key updates from the Polish Ministry of Finance

The Polish Ministry of Finance has been actively working to finalize the technical and procedural aspects of KSeF. Key updates include:

• KSeF 2.0 manual: In September 2025, the Ministry published the “Getting Started Using KSeF – KSeF 2.0 Manual.” This document offers detailed guidance on authentication, data transmission, and managing user roles, particularly for VAT groups and government bodies.
• Technical format: Invoices must adhere to the FA(3) XML format, which is Poland’s version of the European EN 16931 standard. All B2B invoices must be submitted through KSeF, where they will be validated, assigned a unique ID number, and archived.
• Official Timeline for Testing: The Ministry has provided a clear roadmap for the final months leading up to the mandate. Beginning November 1, 2025, the Certificates and Authorization Module (MCU) will launch, allowing taxpayers to download the new KSeF certificates needed for authentication. This coincides with the availability of a test version of the KSeF 2.0 Taxpayer Application, giving businesses a crucial window to test their systems in a near-production environment.
• Offline Procedures: During periods of KSeF system unavailability, companies can issue invoices offline. However, these documents must include a QR code for verification and be uploaded to KSeF by the next business day.
• Unified B2B and B2G Invoicing: Poland is aligning B2B and Business-to-Government (B2G) invoicing. Starting in 2026, government entities will also be accessible through KSeF, allowing businesses to manage both types of transactions within a single system.

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Requirements for Polish large taxpayers by February 2026

If your organization is classified as a large taxpayer, the February 2026 deadline is an immediate priority. Preparing for this mandate requires action across multiple areas of your business:

• Scope: All B2B invoices issued by large taxpayers must be processed through KSeF. This applies to all transactions, regardless of volume.
• Format: Your existing systems must be configured to generate and process invoices in the required FA(3) XML format. This often involves a project to map your current invoice data fields to the new standard.
• Connectivity: High-volume issuers will need to establish an API integration with KSeF to automate the flow of data. While free government tools for manual entry are available for smaller companies, they are not practical for large enterprises.
• Authentication and roles: Organizations must establish secure authentication and define user roles within KSeF. The ability to download certificates starting in November is a critical step in this process.
• Offline procedures: You need to have a clear process for issuing invoices with a QR code when KSeF is down and a mechanism for uploading them to the system the following day.
• Testing and readiness: The KSeF sandbox is an essential tool. Large taxpayers or e-Invoicing compliance platforms they choose, such as Tradeshift, should use this environment to test invoice formats, connectivity, error handling, role assignments, and reconciliation processes to ensure a smooth transition.

Beyond compliance: A strategic opportunity

Compliance projects can be complex, often requiring collaboration between finance, IT, tax, and operations teams. However, viewing this as a simple compliance task can mean missing out on significant benefits. Innovative e-invoicing platforms, such as Tradeshift, can deliver more than just regulatory adherence. They can streamline operations, reduce manual errors, accelerate payment cycles, and provide better visibility into your supply chain through AI-powered reporting & analytics.

Ultimately, a proactive approach to e-invoicing—one that goes beyond meeting the minimum requirements—can help build a more efficient and future-proof finance operation.

Choosing the right technology partner is key. The ideal platform not only meets the specific requirements for Poland but also provides a foundation for future mandates, such as the EU’s ViDA framework. This approach ensures you are not just ticking a compliance box but are also transforming how your business manages invoicing and finance operations globally.

If you are on the lookout for an e-Invoicing compliance platform you’ve arrived at the right place.