Final schema FA_VAT (3) and KSeF 2.0 API documentation published

The final schema FA_VAT (3)open_in_new, developed after multiple public consultations with businesses, will replace the currently applicable version FA_VAT (2) and enter into force on February 1, 2026.

The new API documentationopen_in_new enables integrators to prepare for testing in the KSeF 2.0 TEST environment, which will be available from September 30, 2025. The released materials include:

• API specification in OpenAPI 3.0.4 (JSON) format
• Interactive documentation listing endpoints, parameters, schemas, response codes, and example calls.
• The KSeF 2.0 integrator guide with API usage scenarios (e.g., authentication, invoice submission, UPO retrieval)
• A summary of key KSeF 2.0. API improvements

The MoF has also launched a dedicated KSeF 2.0 informationopen_in_new page in line with the current draft legislationopen_in_new, addressing features that raise questions among the businesses, including:

1. Offline Modes
   • Four offline modesopen_in_new are defined: Offline24, planned maintenance, announced emergency mode, and full system failure.
   • Invoices issued in all offline modes except full system failure, while distributed outside KSeF, must include two QR codes: offline and certyfikat.
2. QR Codes:
   • Two types of QR codesopen_in_new:
     • QR code 1: For invoices issued online via KSeF and shared externally (e.g., cross-border) or for those issued in offline mode with an 'offline' label, providing access to the invoice in KSeF.
     • QR code 2: For invoices issued offline with a 'certyfikat' label, ensuring invoice integrity and authenticity. A KSeF certificate is required to generate this QR code.
3. KSeF Certificates
   • The MoF clarified eligibility and the application process for the KSeF certificatesopen_in_new, which will replace tokens as an authentication method from January 1, 2027.
   • Starting from 1 November 2025, taxpayers and their authorized representatives will be able to apply for the certificate.
   • KSeF certificates are issued with a two-year validity.
4. KSeF Number or Collective ID
   • The MoF outlined the structure and generation of collective IDsopen_in_new via KSeF.
   • , entities, while making payments for e-invoices issued in both online and offline mode, will be required to provide a KSeF number or collective ID on bank transfers.

The KSeF 2.0 legislative process is ongoing, with the draft law currently being reviewed in the lower house of Parliament. According to the MoF, the legislative package is expected to be enacted as announced in July 2025.