Poland Concludes Consultations on KSeF 2.0 Business Event Model
On April 23, 2026, Poland’s Ministry of Finance initiated a public consultation on a proposed business event model and a change synchronization mechanism for the National e-Invoicing System (KSeF). Representing the next developmental phase of the KSeF 2.0 API, this proposal aims to gather market feedback before finalizing the integration architecture.
Technical Synchronization Mechanism
The proposal outlines a target mechanism for exchanging information about invoice modifications. Under this model, KSeF will continue to store the original structured invoices while also recording supplementary business data as separate, linked events. The MoF confirms this approach will not alter the underlying structured invoice data already stored in KSeF.
New Business Event Catalog and Tracking Mechanism
A central component of the MoF's proposal is the introduction of a comprehensive business event catalog. Instead of overwriting an invoice's active status with each update, every operational change will be logged as an independent event with its own identifier and metadata (such as author and creation date). This preserves the historical record, allowing an invoice's current state to be accurately reconstructed from the chronological sequence of recorded events.
Recognizing the multifaceted nature of the proposed event catalog, the MoF advises that detailed discussions regarding specific event types be conducted in separate threads. This ensures the primary focus remains on the broader architectural integration. The consultation highlights several illustrative examples of potential invoice-related events:
- Issuance of initial invoices and subsequent corrections
- Internal qualification statuses (e.g., “to be booked” or “requires clarification”)
- Payment tracking, encompassing both partial and full settlements (currently voluntary; the mandatory requirement to provide KSeF identifiers in bank transfers is scheduled for August 1, 2026)
- Line-item modifications, such as the exclusion of a specific line from settlement
- Fraud and security alerts concerning mass invoice sending, impersonation attempts, or suspicious links
- User-defined business attributes in a key-value format
Expansion of API Operations
To support this model, the proposed KSeF 2.0 API extension will cover two operational categories:
- Read: Downloading or exporting event lists, determining the current invoice status based on events, and extending metadata retrieval to include additional business events.
- Record: Performing operations on invoices that create new business events.
Consultation Timeline
The public consultation period officially closed on May 8, 2026. Market participants were invited to submit their feedback and proposals to the MoF to help shape the final implementation scope. The full technical proposal remains available for review in the official KSeF API documentation.
There’s more you should know about e-invoicing in Poland – learn more about the new and upcoming regulations.
