International PIKON Blog

Poland KSeF 2026: B2B e-invoicing requirement becomes mandatory

Manon Schreurs
August 28, 2025
7 Minutes

The Ministry of Finance in Poland is switching to stricter e-Invoicing requirements by making B2B e-Invoicing mandatory. Poland already introduced their interest in e-Invoicing some years ago by building the PeF platform for voluntary B2G E-Invoicing. From now on, Poland will no longer accept paper invoices for B2B transactions.

Deadlines for Poland B2B e-invoicing KSeF 2026:

Poland’s Ministry of Finance has released updated timelines for the implementation of B2B E-invoicing. The revised schedule is as follows:

Starting from 1st February 2026: B2B e-Invoicing becomes mandatory for large taxpayers with an annual turnover of €43 million or more.
Starting from 1st April 2026: B2B e-Invoicing becomes mandatory for all Polish companies with a Polish VAT registration number and foreign entities with a fixed establishment in Poland.
Starting from January 2027: B2B e-Invoicing becomes mandatory for micro businesses (invoices < 450 PLN and sales per month < 10 000 PLN).

These deadlines provide clarity and ensure a smooth transition for businesses towards adopting electronic invoicing practices in Poland.

For more information about the Poland B2B e-invoicing KSeF 2026, please refer to the official government website of Poland: Link

The Krajowy System e-Faktur to platform (KSeF) will be used as the national Electronic Invoicing system. This means that all electronic invoices must be exchanged through the KSeF platform for validation, ahead of being sent out to the customer.

How will the KSeF platform work?

In general, the KSeF platform will have the following functionalities:

This platform will issue a series of notifications that will inform users of, for example, invoice submission, time stamps, invoice rejection, etc.
Invoices can be searched and downloaded in the original format or in PDF format.
eInvoices are archived for 10 years on the KSeF platform.
Invoices can be issued Online (in real-time) or via the Offline24-modus (allowing invoices to be reported the following day).

On June 30th 2025, an upgraded version of the KSeF platform was announced by the Polish Ministry of Finance: KSeF 2.0. This new e-Invoicing system will go live in February 2026, meaning that businesses will, from then onwards, need to use KSeF for issuing, receiving, and archiving invoices electronically. A unique KSeF ID will be applied to each invoice upon submission, for easy tracking, verification, and management within the platform.

What does the KSeF number consist of?

The KSeF number is a unique number that identifies an invoice in the National e-Invoice System (KSeF). It is made up of the following elements:

The most important updates of the new KSeF version are the following ones:

The XML file format in which e-Invoices should be created, switches from FA (2) to FA (3)
- The main new features of the FA (3) format are: attachment element (Zalacznik), new fields in Podmiot2 (JST, GV) and new roles for Podmiot3.
- Other smaller features are for example the expanded optional fields for a payment link of the invoice, the KSeF payment identifier,…
- The main structure of the FA (3) format will look like this:

KSeF is based on a credential model, which means that authorization and authentication of a person in the system is required to issue and/or access e-invoices. The authorization and authentication can be done in three ways, via:
- Qualified Electronic Signature (QES)
- Trusted profile
- API token (this can be replaced by requesting two-year KSeF issuer certificates, available from November 1st 2025)
B2C invoicing through KSeF is now optional
Any taxpayer that wants to issue e-Invoices via the Offline24 modus, will need special approval. The requirement to request approval first, has nevertheless been postponed and all taxpayers can use the offline mode (Offline24) on a voluntary basis until the end of 2026.

*For more information about SAF-T Poland, please see our dedicated blogpost: SAF-T Poland: Requirements and SAP Compliance Guide – PIKON SAP Consulting International

SAP's Document & Reporting Compliance solution for Poland B2B e-invoicing

SAP released a solution for KSeF e-Invoicing for S/4HANA cloud 2302, S/4HANA on Premise, and SAP ERP systems. Via SAP’s solution, a legally compliant XML file can be automatically generated and sent to the KSeF platform (customer e-Invoicing), and supplier e-Invoices can be pulled into the SAP system from the KSeF portal (supplier e-Invoicing). All aspects are covered under the Document and Compliance (DRC), Cloud Edition functionality and license.

How will the outbound (customer) Poland B2B e-invoicing KSeF 2026 solution work?

When a source document (SD billing document or FI invoice) is created in SAP (and successfully released to accounting), an eDocument is automatically generated in the background. All e-Invoices can be managed from a central eDocument Cockpit. SAP Document and Reporting Compliance (AIF) will map the transactional data from the source document (eDocument) into the required XML format (KSeF FA(2) or FA(3)) and perform a first series of technical checks on format completeness and correctness. After submission to the KSeF platform, the status of the e-Invoice in the eDocument Cockpit will be updated, based on KSeF’s validation response (approval or rejection).

An accepted status means that the eDocument is approved by the government. The KSeF reference number (approval number from the KSeF portal) will become available in the eDocument Cockpit. No further steps are required in case of a domestic customer, who will be able to retrieve the e-Invoice directly form the KSeF portal. In case of a foreign customer, you will need to send the e-Invoice to the customer yourself (which is also possible from the eDocument Cockpit).
A rejected status means that the e-Invoice requires correction. Depending on the rejection message from the government (which is also visible in the eDocument Cockpit), you can either directly correct the e-Invoice and resubmit it, or cancel the eDocument (and source document) and rebill.

Note: KSeF solutions that are available at this moment, are applicable for the FA (2) XML format. Solutions applicable for the FA (3) XML format are announced by SAP but are still under analysis and not available yet.

How will the inbound (supplier) Poland B2B e-invoicing KSeF 2026 solution work?

Your domestic suppliers will create an invoice and send it to the KSeF portal. When the KSeF portal has received and approved the document, you can pull it from the portal into your SAP eDocument Cockpit via a dedicated transaction. The e-Invoice can be displayed in the eDocument Cockpit in both XML and PDF form, and can be forwarded to an automated invoice management solution (e.g. VIM) if desired.

Note: KSeF solutions that are available as of now are applicable for the FA (2) XML format. Solutions applicable for the FA (3) XML format are announced by SAP but are still under analysis and not available yet.

How could PIKON help you?

With our Competence Center for Legal Requirements, we are a strategic partner who ensures that your SAP system and business processes meet different country-specific legal requirements in the long run. We have a team of experts that combine SAP expertise and in-depth knowledge of the end-to-end legal process as well as technical requirements of e-Invoicing and e-Accounting regulations all over the world.

We have gathered this experience through our many SAP Document & Reporting Compliance and local implementation projects all around the world. Some examples are SDI in Italy, SII in Spain, CFDI and Complemento de Pago in Mexico, RTIR and EKAER in Hungary, XRechnung in Germany, the different legal requirements in Turkey, etc. We have also developed our own compliance SAP Add-Ons e.g. MTD VAT in the UK and the VAT Whitelist in Poland.

Furthermore, we always keep an eye on new and changing legal requirements and inform our customers when action is needed. This ensures that your company doesn’t need to follow up on all the legal requirements yourself, and you can concentrate on your daily business.