Poland Tightens KSeF Self-Billing Approval Requirements

Poland's tax authorities have adopted a stricter interpretation of self-billing approval requirements under the country's mandatory KSeF e-invoicing system, creating additional compliance obligations and potential VAT deduction risks for businesses.

Under self-billing arrangements, the buyer issues invoices on behalf of the supplier, subject to an agreement between both parties establishing how invoices will be approved.

Recent tax rulings clarify that suppliers should approve the invoice before it is submitted to KSeF, rather than after issuance. Approval must also relate to the structured XML invoice, meaning that approval of a PDF representation alone is insufficient.

Importantly, KSeF does not currently provide a built-in mechanism for suppliers to approve or reject self-billed invoices, so businesses must manage this process outside the platform.

Implications for Businesses

The stricter interpretation introduces several considerations for companies using self-billing:

• Approval before submission – Suppliers must have an agreed process for accepting invoice content before the XML is transmitted to KSeF
• XML-level approval – Existing processes based solely on PDF approval may no longer be sufficient
• External approval workflows – Businesses must establish approval procedures outside KSeF, with active or tacit acceptance possible under agreed conditions
• VAT deduction risk – Failure to meet the approval requirements could jeopardise the buyer's right to deduct input VAT

The requirements are particularly relevant to enterprises with high-volume self-billing arrangements, where introducing supplier approval before invoice submission may require changes to established ERP and invoicing workflows.

The developments arise from individual tax rulings issued during 2026 rather than a new legislative amendment. Businesses using self-billing should review their existing agreements and approval procedures to ensure they meet the tax authority's interpretation.

Sources:

• Deloitte – KSeF-related Changes and Practical Updates, 29th July 2026
• Polish Tax Ruling – 30th June 2026