National e-Invoice System (KSeF 2.0) – new .NET client library (C#) We are pleased to announce that we have made another client library available on our website and in public repositories, this time for the .NET framework, which facilitates and accelerates the integration of systems and applications with the National e-Invoice System 2.0. These are the final tools 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 two updated client libraries for JAVA and PHP available on our websites and in public repositories, which facilitate and accelerate system integration with the National e-Invoice System 2.0. These are further tools after the KSeF interface. 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 are available at: https://ksefapi.pl/rest-ksef-api-dokumentacja/ Attention! All users who have created accounts 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 (KSEF) approach, entrepreneurs are facing numerous concerns. Concerns expressed by business owners include adapting their company software to the new requirements and the security of data transferred to the government's KSeF IT system. What data is stored in the system? Read more…
Standardized invoices are those in XML format and stored electronically. A PDF file is generated when the document needs to be read, and KSeF has introduced a new requirement to mark invoice visualizations with QR codes. This code allows for easy verification that the document was generated in KSeF and that all information is correct. Read more…
As of February 1, 2026, many companies will be required to issue structured invoices through the National e-Invoice System. Implementing KSeF in a company comes with many challenges, one of which is the authorization process using KSeF certificates. Learn what a KSeF certificate is, what it's used for, and how to obtain it. Read more…
The National System for E-Invoices (KSeF) is a hot topic in 2025. Many businesses are looking for reliable information, as the Ministry of Finance has changed the guidelines for this solution several times, including postponing the effective date of the KSeF regulations. The following guide is a compendium of knowledge about the KSeF, presenting the status as of July 2025 – we invite you to read it. Read more…
Implementing the National e-Invoice System (KSeF) is one of the biggest technological challenges facing Polish companies today. The complexity of the official API, limited access to documentation, and lack of efficient technical support are forcing many organizations to rely on the services of investors. One of the leaders in this field is ksefapi.pl, a solution that Read more…
An invoice correction note is a document that allows you to correct minor errors on a sales invoice without having to issue a correction invoice. When can it be used and who is authorized to do so? Read this article to learn the rules and avoid errors that may have tax consequences. What is an invoice correction note? Read more…