Obligation to issue e-Invoice in KSeF: large enterprises from 1.02.2026, others from 1.04.2026.
KSeF National e-Invoicing System, structured e-invoice and 2026 mandate — implementation deadlines, receipt obligation and delivery to Polish SMEs
The National e-Invoicing System (KSeF) becomes mandatory for all Polish VAT taxpayers from 1 February 2026 for large enterprises (over PLN 200 million turnover) and from 1 April 2026 for the rest. Structured e-Invoice in XML format (FA(2) schema) is the only permitted format. 4notify integrates with the major Polish accounting systems (Comarch, Asseco, Sage Symfonia, iFirma) and delivers receipt confirmations, validation reports and delivery notifications.
Pursuant to the Act of 16 June 2023 amending the VAT Act (Journal of Laws 2023 item 1598) introducing the e-Invoice obligation in KSeF, the Minister of Finance issues the following Notice on the delivery of receipt confirmations and validation reports via 4notify Operations.
Statutory basis for introducing the e-Invoice obligation in the Polish tax system.
Structured e-Invoice XML schema — only permitted format in KSeF.
Webhook Comarch / Asseco / Sage Symfonia
4notify subscribes to e-Invoice queue in accounting system; FA(2) validation before sending to KSeF.
Receipt confirmation with validation report
Receipt confirmation within 60 seconds to issuer; validation status (accepted / with remarks / rejected) after 5 minutes.
Delivery to correct accountant
With accountancy NIP, confirmation directed to the correct accountant; copy to tax adviser.
5-year retention (Tax Ordinance)
Every invoice and confirmation with hash signature retained 5 years per Tax Ordinance art. 86.
xml
<eFaktura-odbior xmlns="https://4notify.net/ksef/v1">
<numer_faktury>FV/2026/05/27/481923</numer_faktury>
<nip_odbiorca>1234567890</nip_odbiorca>
<nip_wystawca>9876543210</nip_wystawca>
<format>FA(2)</format>
<walidacja_status>zaakceptowana</walidacja_status>
<potwierdzenie_do>email,webhook</potwierdzenie_do>
<biuro_ksiegowe_nip>5555555555</biuro_ksiegowe_nip>
<ksef_uuid>e-Faktura-2026-XXX-481923</ksef_uuid>
</eFaktura-odbior>Dear Sir or Madam, we have received your FA(2) e-Invoice number FV/2026/05/27/481923 and validated it on 27.05.2026 at 14:32. Validation status: accepted Forwarded to: Jan Kowalski Accounting Office (NIP 5555555555) Kind regards, 4notify Operations
- Webhook Comarch / Asseco / Sage Symfonia / iFirma installed
- FA(2) v2.5 validation at API edge
- P50 receipt confirmation ≤ 60 seconds measured
- 5-year audit retention documented
4notify is the only A2P provider with native Comarch / Asseco / Sage Symfonia integration, FA(2) v2.5 validation at API edge, P50 ≤ 60 seconds receipt confirmation and 5-year audit retention compliant with Tax Ordinance art. 86.
Does 4notify also support older JPK_FA format?
Yes — JPK_FA remains available for historical transactions and taxpayers not covered by KSeF mandate (e.g. consumers).
What happens with rejected validation?
Issuer receives validation report with detailed errors and correction guidelines. Rejected invoice not imported to KSeF.
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