
Mandatory KSeF - why is it important for all businesses?
- In the near future, all invoices in B2B transactions between VAT-registered taxpayers in Poland will be sent and received exclusively through the National e-Invoicing System (KSeF).
- The mandatory implementation of the system, originally planned for July 1, 2024, has been postponed to February 1, 2026, for taxpayers whose turnover in 2025 exceeds PLN 200 million and to April 1, 2026, for other taxpayers.
- The system will also cover foreign entities that have a permanent place of business in Poland (so-called fixed establishment).
- Invoices issued by Polish taxpayers to foreign contractors (e.g., for intra-Community supply of goods, export of goods, or export of services) will also have to be issued in KSeF, but their delivery will be arranged in agreement with the contractor.
- Although the VAT Act amendment initially set to take effect on July 1, 2024, intended to exclude B2C invoices entirely from KSeF, the obligatory version coming into force on February 1, 2026, will allow B2C invoices to be included in KSeF on a voluntary basis—detailed regulations in this regard are not yet known.
- For some industries, a special solution is planned in the form of a structured attachment to the e-invoice.
Implementing KSeF is a complex and time-consuming process. It involves not only technical aspects but also the need for significant changes in internal processes, procedures, contracts, and regulations. From our practical experience in KSeF implementation projects, typical challenges include the inability to send invoice attachments in KSeF or difficulties in accounting for invoices due to the waiting period for their validation in KSeF.
Regardless of the final deadline for the mandatory implementation of KSeF, we recommend that your company start preparing for its operation in KSeF as early as possible.
Benefits of using structured invoices
Benefits for entrepreneurs:
- No need to archive documents. The system will store them for a statutorily defined period of 10 years;
- Shortening of the period for VAT refunds from 60 to 40 days;
- Speed of procedures;
- Certainty that the invoice has been delivered to the contractor. Efficiency of business processes;
- The structure of the Standard Audit File for Tax [Jednolity Plik Kontrolny] (JPK_FA) for invoices issued in KSeF will be available to the tax authorities directly from KseF;
- One document template and ease of reading.
How can we help you?
We can offer your company various forms of support in the complicated and complex undertaking which is the KSeF implementation:
- Preparing a KSeF implementation plan, considering technological aspects, defining the scope of IT system functionalities, and determining the necessary changes in internal processes, procedures, contracts, and regulations;
- Defining and mapping specific data from company systems that will be covered by the new structured invoice scheme;
- Identifying potential risks related to the invoicing model change and introducing measures to secure the company;
- Coordinating project team efforts, including support in communication between tax/accounting/finance and IT departments;
- Preparing changes in internal company processes and procedures, contract clauses, and regulations to adapt to the new invoicing and document flow model, including structured invoice issuance and receipt, internal invoice approval, VAT reporting and settlement, and granting/revoking KSeF access;
- Conducting system tests for issuing and receiving structured invoices in KSeF;
- Verifying generated invoices using the proprietary MDDP KSeF Validator tool.
These sessions include a detailed discussion of KSeF operation principles and practical challenges associated with its implementation.
Tailored to the specifics of your company’s operations, focusing on practical aspects of implementing and using new solutions.
We will provide a detailed overview of technical and substantive issues, including granting permissions, authentication, invoice sending and receiving in KSeF, as well as an analysis of all structured invoice fields, considering both mandatory and optional elements.
In cooperation with an IT partner, we offer also technical support under the implementation process and provide a tool for communication with KSeF regarding the issuing and receipt of structured invoices.
Advantages of the tool:
- Easy integration with various systems.
- Technical validation of an invoice before shipment.
Contact us:

Tomasz Michalik
Partner | Tax Adviser
E: tomasz.michalik@mddp.pl
T: (+48) 501 733 720

Janina Fornalik
Partner | Tax Adviser
E: janina.fornalik@mddp.pl
T: (+48) 660 440 141

Krzysztof Jaros
Manager | Tax Adviser
E: krzysztof.jaros@mddp.pl
T: (+48) 504 399 980

Magdalena Krzemińska
Manager
E: magdalena.krzeminska@mddp.pl
T: (+48) 503 973 001
Related content
Benefits for entrepreneurs:
- No need to archive documents. The system will store them for a statutorily defined period of 10 years;
- Shortening of the period for VAT refunds from 60 to 40 days;
- Speed of procedures;
- Certainty that the invoice has been delivered to the contractor. Efficiency of business processes;
- The structure of the Standard Audit File for Tax [Jednolity Plik Kontrolny] (JPK_FA) for invoices issued in KSeF will be available to the tax authorities directly from KseF;
- One document template and ease of reading.
Moreover, the SLIM VAT 3 package includes:
- Simplifications in the determination of conversion rates to PLN for corrective invoices;
- Increase in the sales value limit for small taxpayers up to EUR 2 million;
- Simplification in settling the intra-Community acquisition of goods (WNT) – no requirement to have an invoice to deduct VAT;
- Simplifications in the scope of VAT ratio – i.e., replacing the obligation to agree on the proportions in the form of a report with a notification submitted to the Head of the Tax Office;
- Abolition of the obligation to print fiscal documents.
Benefits for entrepreneurs:
- No need to archive documents. The system will store them for a statutorily defined period of 10 years;
- Shortening of the period for VAT refunds from 60 to 40 days;
- Speed of procedures;
- Certainty that the invoice has been delivered to the contractor. Efficiency of business processes;
- The structure of the Standard Audit File for Tax [Jednolity Plik Kontrolny] (JPK_FA) for invoices issued in KSeF will be available to the tax authorities directly from KseF;
- One document template and ease of reading.
Moreover, the SLIM VAT 3 package includes:
- Simplifications in the determination of conversion rates to PLN for corrective invoices;
- Increase in the sales value limit for small taxpayers up to EUR 2 million;
- Simplification in settling the intra-Community acquisition of goods (WNT) – no requirement to have an invoice to deduct VAT;
- Simplifications in the scope of VAT ratio – i.e., replacing the obligation to agree on the proportions in the form of a report with a notification submitted to the Head of the Tax Office;
- Abolition of the obligation to print fiscal documents.