KSeF 2026: Mandatory e-Invoicing System Will Require Contract and Process Updates
As of February 1, 2026, Poland’s National e-Invoicing System (KSeF) will become mandatory. This is not only a revolution in accounting and IT, but also a turning point for business contracts and compliance procedures. Companies should act now to avoid disputes and tax risks.
The mandatory implementation of the National e-Invoicing System (KSeF) on February 1, 2026, will significantly affect the way businesses operate. The reform goes far beyond accounting departments – it requires a thorough review of contracts with counterparties and accounting firms.
According to Cezary Madeka, tax advisor and manager in the VAT team at Thedy & Partners, companies should already be preparing to:
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amend contract provisions on invoice delivery and receipt,
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determine whether payments will be based solely on invoices issued in KSeF,
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define the scope of data and approval procedures for invoices,
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adjust payment terms to reflect the new regulations.
Failing to clarify these issues may lead to contractual disputes and tax risks – for example, if a counterparty issues an invoice outside the KSeF system.
Experts emphasize that now is the right time to audit internal procedures, assess risks, and update agreements with contractors and accounting partners. Proper preparation will minimize complications once KSeF becomes mandatory.