KSeF — Poland’s National e-Invoicing System: What’s Changed and What to Do Now

Poland’s National e-Invoicing System (KSeF) is no longer a future obligation — it is live. On 27 August 2025, Poland’s President signed into law the amendment to the Value-Added Tax Act, establishing the Krajowy System e-Faktur (KSeF) as a mandatory national e-invoicing system, effective from 1 February 2026. For most businesses, the transition is already underway or has already taken effect. 

What is KSeF?

KSeF is Poland’s centralised electronic invoicing platform developed and operated by the Ministry of Finance. It requires structured invoices to be issued and received in XML format (the FA(3) schema, which replaced FA(2) from February 2026), stored centrally and assigned a unique KSeF identification number. The system validates invoice content automatically and serves as the official repository for business-to-business (B2B) and business-to-government (B2G) invoices. Since January 2022 the system had operated on a voluntary basis — that phase is now over.

Implementation timeline — KSeF 2.0

The mandatory rollout follows a phased schedule based on 2024 annual gross sales:

• 1 February 2026 — mandatory for large taxpayers with 2024 gross sales exceeding PLN 200 million.
• 1 April 2026 — mandatory for all other VAT-registered entities, including SMEs and sole proprietors.
• 1 January 2027 — mandatory for micro-entrepreneurs with monthly sales under PLN 10,000.

Since 1 February 2026, all taxpayers have been required to be able to receive invoices through KSeF, even if they are not yet obliged to issue them via the system. 

Penalty grace period

The Ministry of Finance confirmed that no penalties will be imposed for errors in using KSeF until 31 December 2026. This penalty-free period is intended to give businesses time to stabilise processes, train staff and resolve technical issues without enforcement risk. Financial penalties for non-compliance begin applying from 1 January 2027. 

Temporary exemptions during 2026

Several categories remain outside the mandatory scope until the end of 2026 or until 1 January 2027:

• Invoices under PLN 450 gross can continue in the old format until 30 September 2026.
• Taxpayers who issue simplified invoices for low amounts (up to PLN 450 per invoice or PLN 10,000 per month) may continue to use the current format until 30 September 2026.
• Voluntary use of offline mode is permitted until 31 December 2026.
• Certain transactions remain exempt from structured e-invoicing due to technical constraints, including highway tolls, passenger transportation tickets, and selected financial or insurance services.

KSeF number in bank transfers

The obligation to include the KSeF number in bank transfers (including payments with the split payment mechanism) will apply to payments made from 1 August 2026. 

Key technical changes — FA(3) schema

The FA(3) schema replaced FA(2) from 1 February 2026. Businesses must ensure their accounting and ERP systems issue invoices using the updated schema. The KSeF 2.0 API is the only channel for production submissions — KSeF 1.0 ceased functioning on 1 February 2026.

Authentication is handled via KSeF certificates, qualified electronic seals or signatures, or tokens. The ZAW-FA form must be submitted by entities other than natural persons to authorise users to issue invoices through the system.

Foreign businesses with VAT registration in Poland

The obligation to issue e-invoices via KSeF does not apply to businesses that do not have a registered office or a permanent establishment in Poland, or that have a permanent establishment in Poland but that establishment does not participate in the delivery of goods or provision of services for which invoices are issued. Foreign businesses registered for VAT in Poland should verify their position against these criteria. 

Benefits confirmed in practice

The key benefits described in earlier guidance remain accurate:

• VAT refund period shortened from 60 to 40 days for KSeF users.
• No obligation to maintain separate invoice archives — KSeF stores invoices for 10 years.
• Simplified handling of corrective invoices and elimination of duplicate invoice obligations.
• Automatic integration of KSeF data with JPK_VAT reporting.
• Improved process automation and reduced risk of invoicing errors.

What businesses should do now

For those already subject to mandatory KSeF (large taxpayers from February, all other VAT-registered entities from April), the priority is stabilising processes during the grace period before penalties apply in January 2027. For micro-entrepreneurs with the January 2027 deadline, preparation should begin in Q3–Q4 2026 to avoid the implementation bottlenecks that many larger businesses experienced.

Practical steps include: updating accounting or ERP systems to support FA(3) XML format and KSeF API integration; submitting the ZAW-FA authorisation form; training employees on the new invoicing workflows; and testing the ability to both issue and receive invoices through the system.

For questions about KSeF compliance or VAT obligations in Poland, please contact our team: Contact us — amavat®