Dear Sir or Madam, Due to planned maintenance work, we would like to inform you that on Saturday, February 21, 2026, from 10:00 PM to 2:00 AM on February 22, 2026 (Sunday), there will be a break in access to the website and API interface. The work will be related to increasing security. Read more…
National e-Invoice System (KSeF 2.0) – new .NET client library (C#) We are pleased to announce that we have made available on our websites and in public repositories another client library, this time for the .NET framework, which facilitates and accelerates the integration of systems and Read more…
National e-Invoice System (KSeF 2.0) – new client libraries for PHP and JAVA We are pleased to announce that we have made available on our websites and in public repositories, two updated client libraries for JAVA and PHP, which facilitate and accelerate the integration of systems with Read more…
Dear Sir or Madam, We would like to inform you that we have made it possible to register and create accounts on our website for the KSeF 2.0 test environment. The website enabling registration and account creation: https://ksefapi.pl/portal-test/register Login to the user panel: https://ksefapi.pl/portal-test/login Instructions on how to configure an account and start using the provided API Read more…
We would like to inform you that the updated version of the ksefapi.pl interface for the KSeF 2.0 architecture is now available: https://ksefapi.pl/public/rest/ We plan to launch registration and account creation on January 12, 2026. KSeF API Team
As the new regulations requiring the use of the National e-Invoice System approach, entrepreneurs are facing many concerns. Concerns expressed by business owners include adapting their company software to the new requirements and the security of data being transferred. Read more…
Standardized invoices are those in XML format and stored electronically. A PDF file is generated when the document needs to be read. KSeF has introduced a new requirement to mark invoice visualizations with QR codes. This code allows for easy verification, Read more…
As of February 1, 2026, many companies will be required to issue structured invoices through the National e-Invoice System. Implementing the KSeF system in a company presents many challenges, one of which is the authorization process using KSeF certificates. Learn more Read more…
The National System of e-Invoices (KSeF) is a very popular topic in 2025. Many entrepreneurs are looking for reliable information, as the Ministry of Finance has changed the assumptions of this solution several times, including postponing the effective date of the regulations regarding KSeF. The following guide is a compendium of knowledge about Read more…
Need intuitive and functional business software? Then learn more about the software offered by the third-party provider KSeF API. It's a good alternative to the official National e-Invoice System. What can you gain by using ready-made libraries, comprehensive documentation, and Read more…