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Mandatory e-Invoicing System in Poland –What Foreign Businesses Should Know

May 28, 2026

AGN EMEA Tax Committee News

Poland is moving ahead with mandatory e-invoicing, having officially introduced mandatory e-invoicing through the National e-Invoicing System, known in Polish as Krajowy System e-Faktur (KSeF). The reform represents one of the biggest changes to the Polish VAT compliance landscape in recent years.

Introduction of KSeF

The introduction of KSeF places Poland among the European frontrunners in digital tax reporting and invoicing. While the European Union is still working on the VAT in the Digital Age (ViDA) package, which will eventually introduce harmonised e-invoicing rules across the EU, Poland has decided to move forward earlier with its own domestic solution.

The new obligations were introduced in phases. Mandatory KSeF applies from 1 February 2026 for the largest taxpayers, while for all remaining businesses the obligation became effective from 1 April 2026.

Who is covered by the e-invoicing obligation?

As a general rule, mandatory e-invoicing applies to all Polish VAT taxpayers, regardless of their size or turnover. This includes both large corporations and small businesses operating in Poland. The obligation also extends to foreign businesses that have a fixed establishment in Poland for VAT purposes.

Foreign companies without a fixed establishment in Poland are not required to use KSeF. However, if such businesses hold a Polish VAT number, they may still use the system voluntarily and issue invoices through KSeF on an optional basis.

Which transactions are subject to e-invoicing?

The obligation applies regardless of the invoice value—there are no minimum thresholds. KSeF mandatory e-invoicing primarily covers B2B transactions. Invoices issued to private individuals (B2C) may also be issued through KSeF, but this remains optional.

Transactions reported under the OSS (One Stop Shop) scheme are excluded from the mandatory KSeF system. Businesses using OSS for cross-border sales within the EU therefore do not report those invoices through KSeF.

How does the system work in practice?

From a technical perspective, invoices are issued in a strictly defined electronic format based on XML structures. The invoice is then transmitted directly to the governmental platform operated by the Polish Ministry of Finance. After successful processing, each invoice receives its own unique KSeF ID, in addition to the regular invoice number assigned by the seller. Buyers also access and download purchase invoices directly through the Ministry’s platform.

As a result, the traditional circulation of invoices between businesses is effectively replaced by a centralised governmental platform through which all invoices pass.

What are the first impressions after implementation?

Overall, the rollout of mandatory e-invoicing in Poland has been relatively smooth. However, like any large-scale digital reform, the first weeks brought some technical issues and temporary system challenges. The platform is now operating efficiently and has proven to be stable and capable of handling large volumes of invoices. According to data presented by the Polish Ministry of Finance, approximately 135 million invoices were issued through KSeF during the first two weeks of April alone, demonstrating both the massive scale of the system and the high level of adoption among businesses in Poland.

The implementation was preceded by a broad information campaign, giving businesses sufficient time to adapt their accounting and ERP systems to the new requirements.

It is also worth noting that the Polish authorities have adopted a relatively soft landing approach. Although KSeF becomes mandatory in 2026, administrative penalties for non-compliance are scheduled to apply only from 2027, giving businesses additional time to fully adapt to the new system.