Poland: KSeF e-invoicing mandatory for all VAT taxpayers (except the smallest micro-firms)
Since 1 April 2026 all businesses in Poland must issue B2B invoices through the National e-Invoicing System (KSeF) in the FA(3) XML schema; the system assigns the legal invoice number and the buyer receives it via KSeF. Only micro-entrepreneurs with monthly sales up to PLN 10,000 (gross) have until 2027. Paper and PDF invoices are no longer valid B2B invoices.
Connect your ERP or invoicing tool to KSeF 2.0 with authentication tokens or a qualified signature, implement the FA(3) schema and offline24 fallback mode, and train staff on retrieving purchase invoices from KSeF. Use the 2026 penalty-free period to fix errors.