E-invoicing-KSeF 2.0 API Testing begins: the Ministry of Finance opens integration Environment

Poland’s Ministry of Finance has opened the integration environment for KSeF 2.0 API testing, allowing software providers to check system compatibility ahead of the mandatory rollout. A detailed user manual and technical support are available, with key milestones leading up to the full production launch on February 1, 2026.

On September 30, 2025, the Ministry of Finance of Poland officially launched open testing for the KSeF 2.0 API, a key step in preparing for the mandatory rollout of the updated National e-Invoice System.

The test (integration) environment allows financial and accounting software providers to check how their systems interact with KSeF 2.0. This integration is essential to ensure full compliance with the upcoming mandatory version of the system.

To help users, the Ministry has published the KSeF 2.0 Manual, a four-part guide covering:

·         Basic system info and key dates

·         How to issue, receive, and manage e-Invoices

·         Advanced features like attachments and offline handling

·         Special rules for local governments and VAT groups

The manual and technical support are available through the official KSeF website: ksef.podatki.gov.pl/formularz

Upcoming dealines:

·         October 15: Pre-production (DEMO) environment goes live

·         November 1: Certificate and Authorization Module (MCU) launches

·         November: DEMO version of the KSeF Taxpayer App becomes available

·         January 1, 2026: Reporting module launches in the e-Tax Office

·         February 1, 2026: Full production version of KSeF 2.0 goes live

The Ministry encourages all integrators to begin testing now and use the available support to ensure a smooth transition.