Poland launches first wave of mandatory KSeF B2B E-invoicing-overview

Poland has launched the first phase of mandatory B2B e-invoicing via the National e-Invoice System (KSeF), requiring large taxpayers (PLN 200m+ turnover) to issue invoices through KSeF from 1 February 2026, with wider rollout in April 2026 and micro-enterprises joining in 2027. Final regulations from the Polish Ministry of Finance confirm the FA(3) XML standard, phased compliance milestones, transitional penalty relief in 2026, and a broad mandate covering domestic B2B, B2G, and outbound cross-border transactions, with central 10-year invoice storage and API-based connectivity.

The Polish Ministry of Finance has officially launched the first wave of mandatory B2B e-invoicing through the National e-Invoice System (KSeF). Large taxpayers with annual turnover above PLN 200 million are now required to issue invoices via KSeF. The rollout continues on 1 April 2026 for most other businesses, while micro-enterprises will join on 1 January 2027.

Key developments:

• 27 January 2026: The Ministry introduced KSeF Latarnia, a GitHub-based service providing technical access times and maintenance updates.
• 18 December 2025: Final regulations were published, covering exemptions, invoicing rules, and links to SAF-T VAT reporting.

Timetable highlights:

• 1 Feb 2026: Large taxpayers go live.
• 1 Apr 2026: Other taxpayers join.
• 1 Aug 2026: Bank transfer ID references must be added.
• Jan 2027: Micro businesses enter the system.

Scope of the mandate

• Mandatory: Domestic B2B supplies, sales to public bodies (B2G), and outbound cross-border transactions.
• Excluded: Domestic B2C invoices, inbound cross-border invoices from non-Polish suppliers, and certain exemptions such as small taxpayers or OSS/IOSS transactions.

Regarding technical standards, we can say that Invoices must follow the FA(3) XML schema, aligned with European standards (EN 16931, Peppol BIS). Each invoice receives a unique KSeF reference number and QR code for verification. No electronic signature is required, as authenticity is ensured by KSeF itself.

Compliance and penalties:

• 2026: Transitional relief – no monetary penalties for breaches.
• 2027 onwards: Administrative fines apply for non-compliance.

Retention: All invoices are stored centrally by the tax authority for 10 years, reducing the burden on businesses.

Businesses can connect via APIs, government portals, or simplified tools for micro-enterprises. Invoices are validated automatically; only approved invoices are legally recognised. Offline submission is permitted under the permanent Offline24 mode, with next-day uploads required.