KSeF from 2026! What does the postponement mean and how to prepare your company for mandatory e-invoicing?

The National e-Invoicing System (KSeF) is an inevitable revolution in the way invoicing is done in Poland. After many discussions and expectations, the Sejm passed a law introducing mandatory e-invoicing, setting new effective dates for the system. This is key information for all entrepreneurs: mandatory KSeF will come into force on February 1, 2026, for most companies, and on April 1, 2026, for small VAT-exempt companies. Despite the postponement of the original deadlines, there is still time to prepare, and now is the moment to act proactively. In this article, you will learn what KSeF is, what changes it introduces, what the current implementation schedule is, and how to effectively prepare your company for the upcoming obligations. Get ready for e-invoicing with us!

KSeF: system basics and operation principles

The National e-Invoicing System (b) is a central IT platform designed to revolutionize the circulation of accounting documents in Poland. Its main goal is to standardize the process of issuing, receiving, and storing VAT invoices. A key element of the system is the structured e-invoice, which is a document issued and received via KSeF, compliant with the FA_VAT logical structure provided by the Ministry of Finance. Such an invoice has legal precedence over other forms of documents.

How does KSeF work?

The KSeF system acts as a centralized hub through which all VAT invoices pass. The process is as follows:

1.Invoice Issuance: an entrepreneur issues an invoice in their financial and accounting system and then sends it to KSeF.

2.Verification and Assignment of ID: bverifies the invoice’s correctness against the logical structure. After successful verification, the system assigns a unique identification number (KSeF ID) and the date of its receipt to the invoice.

3.Recipient Access: the invoice recipient gains access to it in their KSeF panel, eliminating the need to send invoices via email or postal mail.

Who will be covered by the obligation?

The obligation to use bwill cover a wide range of entities. According to current regulations, these will include:

•Active VAT taxpayers,

•VAT-exempt taxpayers (both subjectively and objectively),

•Foreign entities with a permanent establishment in Poland.

Main goals of KSeF implementation

The introduction of KSeF is expected to bring several benefits from the state’s perspective, including:

•Sealing the tax system: Thanks to data centralisation, tax authorities will have real-time insight into transactions, which is intended to limit tax fraud and the grey economy.

•Process automation: The system is designed to streamline control and analytical processes for the administration, and also to accelerate VAT refunds for entrepreneurs.

•Increased transparency: Full transparency of invoice circulation is expected to contribute to improved tax discipline.

Current KSeF schedule: new effective dates for the system

The most significant change, which caused the most emotion and uncertainty in the business community, is the postponement of the effective date of mandatory KSeF. Originally, the system was supposed to become obligatory as early as July 1, 2024, and then January 1, 2025, for small and medium-sized enterprises. However, after an audit and extensive public consultations, including those conducted on the b.podatki.gov.pl platform, the Ministry of Finance decided to change the schedule. The Sejm passed an amendment to the VAT Act, which introduces new, official dates.

New, official effective dates for KSeF:

•February 1, 2026: obligation to use KSeF for most entrepreneurs, i.e., active VAT taxpayers. This applies to companies whose sales value (including the tax amount) exceeded PLN 200 million in 2024

•April 1, 2026: obligation for small VAT-exempt companies, both subjectively (due to turnover) and objectively (due to the type of business conducted).

The postponement of deadlines is a result of the need to refine the system, which showed some imperfections in the initial testing phase and raised concerns among entrepreneurs. As emphasised by the Ministry of Finance, this is intended to give companies more time to properly prepare for the changes, implement necessary IT solutions, and train personnel. This is an opportunity, not a reason for inaction – the sooner a company starts the adaptation process, the smoother the transition to the new invoicing model will be.

Key changes for entrepreneurs after KSeF implementation

The introduction of KSeF entails a series of significant changes that will affect every entrepreneur in Poland. Understanding these modifications is crucial for a smooth transition to the new system. Below are the most important aspects to pay attention to:

Issuing invoices

From the effective date of the obligation, the only legally binding form of invoice for transactions covered by KSeF will be a structured invoice issued through the system. This means the end of issuing paper or PDF invoices for most B2B transactions. Invoices will have to be generated in accounting systems compatible with KSeF and sent to the National e-Invoicing System, which will assign them a unique identification number (KSeF ID).

Receiving invoices

Similar to issuing, receiving invoices will also take place via KSeF. Entrepreneurs will be obliged to download invoices from the system, which means that traditional methods of delivering invoices, such as email or postal mail, will no longer be sufficient. Access to invoices in KSeF will be available in real-time, which is intended to streamline accounting and settlement processes.

Invoice identification number (KSeF ID)

Each structured invoice, after successful submission to KSeF and verification, will receive a unique KSeF ID. This number will confirm that the invoice has been correctly accepted by the system and is available to the recipient. This will be a key element in communication between contractors and with tax authorities.

Authorisation and authentication

Access to KSeF and the ability to issue and receive invoices will require appropriate authentication. Available authorisation methods include:

•Qualified electronic signature,

•Qualified electronic seal,

•Trusted Profile (Profil Zaufany),

•KSeF token – a specially generated string of characters that can be used to authorize accounting systems.

Entrepreneurs will need to ensure that appropriate individuals in the company have access to these authorization tools.

Corrective invoices and cancellation

Handling corrective invoices and cancelling invoices will also take place via KSeF. The system will require corrections to be sent in a structured form, which will ensure data consistency and facilitate their verification. The rules for cancelling invoices, although still under discussion, will have to comply with KSeF procedures.

Transitional periods and exclusions

The draft law provides for certain transitional periods and exclusions from the KSeF obligation. The most important of these include:

•Tickets treated as simplified invoices: In the initial period of KSeF operation, tickets (e.g., receipts with NIP up to PLN 450) may still be treated as simplified invoices and will not have to be sent via KSeF.

•Invoices from cash registers: Invoices issued using cash registers will also be excluded in the initial period.

•B2C sales: Invoices issued to consumers (B2C) will not be covered by the KSeF obligation. The system primarily concerns B2B (Business to Business) transactions.

Changes in invoice storage

One of the key benefits of KSeF is that the system will serve as a central archive for invoices. All structured invoices that pass through KSeF will be stored in the system for a period of 10 years, counting from the end of the year in which they were issued. This means a significant simplification for entrepreneurs in terms of document archiving and the elimination of the risk of losing them.

How to prepare your company for KSeF? A practical guide

The postponement of KSeF’s effective date provides valuable time that should be used to properly prepare your company. The sooner you start, the smoother the adaptation to the new system will be. Here’s a practical guide to help you through this process:

1. Audit your current IT systems

The first step should be a thorough check to see if your current financial and accounting software (ERP, invoicing systems, accounting programs) is ready for integration with KSeF. Contact your solution providers and find out if they plan updates or new modules supporting KSeF. If your software is not compatible, consider updating it or switching to one that meets KSeF requirements. Remember that system integration is often a complex and time-consuming process.

2. Choose your integration method

The Ministry of Finance provides several methods for integration with KSeF, offering entrepreneurs some flexibility in choosing the most suitable solution:

•API (Application Programming Interface): For companies with extensive IT systems, integration via API will be the most effective solution. This will allow for automatic data exchange between your system and KSeF.

•Dedicated software: more and more dedicated programs are appearing on the market that are used exclusively for KSeF operations. These can be a good solution for smaller companies that do not need full ERP integration.

•Free tools from the Ministry of Finance: The Ministry of Finance provides free tools, such as the KSeF Taxpayer Application or a web interface. These are basic solutions that may be sufficient for the smallest entities or for testing the system.

•Accounting office: cooperation with an accounting office that offers KSeF services is often the simplest solution for many companies. The office can take over the obligation of issuing and receiving invoices via KSeF, minimizing the burden on the entrepreneur.

3. Authentication and authorisation

Ensure that the people responsible for invoicing and accounting in your company have the appropriate tools for authentication in KSeF. This can be a qualified electronic signature, a qualified electronic seal, or a Trusted Profile (Profil Zaufany). Make sure that all employees who will interact with KSeF have current and valid certificates or profiles.

4. Employee training

KSeF is a change that will affect not only the accounting department but also other departments, such as sales and administration. It is necessary to train personnel in new procedures for issuing and receiving invoices, operating the system, and resolving potential problems. Investing in training will pay off in a smoother transition to the new system and avoidance of errors.

5. System testing

The Ministry of Finance provides a KSeF test environment that allows you to familiarise yourself with the system’s operation without risk. We encourage active use of this environment to test invoice issuance and receipt processes, check integration with your software, and identify potential problems. Testing is the best way to prepare for real implementation.

6. Cooperation with an accounting office

The role of an accounting office in the KSeF adaptation process is invaluable. An experienced office can provide comprehensive support, including:

•Implementation: assistance in selecting and configuring appropriate IT solutions.

•Support: ongoing advice and problem-solving related to KSeF.

•Interpretation of regulations: explaining the legal and tax complexities associated with e-invoicing.

An accounting office can become your partner in this process, minimising stress and ensuring compliance with new regulations.

Benefits and challenges of KSeF for entrepreneurs

The introduction of the National e-Invoicing System, while a significant challenge, also brings a number of potential benefits for entrepreneurs. It is important to look at KSeF from both perspectives to fully assess its impact on business operations.

Potential Benefits of KSeF:

•Automation of invoicing and settlement processes: KSeF is intended to streamline and automate the circulation of invoices, which will save time and resources currently spent on manual data entry, printing, and archiving documents.

•Data security and no lost invoices: all invoices stored in KSeF will be secure and always accessible. This eliminates the risk of losing, destroying, or incorrectly accounting for invoices, which often happens with paper documents.

•Faster VAT refunds (potentially): thanks to real-time access to transaction data, tax authorities will be able to verify VAT declarations more quickly, which in the future may translate into shorter refund periods for overpaid tax.

•Reduced document storage costs: the obligation to store invoices in KSeF for 10 years means that entrepreneurs will not have to bear the costs associated with physical archiving of documents, which is particularly beneficial for companies generating a large number of invoices.

•Simplification of JPK_V7 generation: data from structured invoices will already be available in the system, which in the future may significantly simplify the process of generating the Uniform Control File for VAT (JPK_V7), minimizing the risk of errors.

Challenges associated with KSeF implementation:

•Costs of IT system implementation and adaptation: The biggest challenge for many companies will be the costs associated with adapting or purchasing new software that will be compatible with KSeF. This often requires investment in IT infrastructure and system integration.

•Need for staff training: New procedures and KSeF system operation will require employee training, which involves additional costs and time. Insufficient training can lead to errors and delays.

•Risk of failures and technical errors in the initial phase: Like any new system, KSeF may be prone to failures and technical errors, especially in the initial period of operation. This can lead to invoicing downtime and cash flow problems.

•Dependence on KSeF system stability and availability: Entrepreneurs will be fully dependent on the proper functioning of the KSeF system. Any interruptions in its operation can directly affect the ability to issue and receive invoices.

•Initial increase in employee workload: Despite the prospect of automation, in the initial phase of KSeF implementation, it may mean an increase in workload for employees who will have to master new tools and procedures.

Conclusion and Accounting firm recommendations

The National e-Invoicing System is undoubtedly one of the biggest changes in the Polish tax system in recent years. Despite the postponement of its effective date, KSeF will become a mandatory reality for most entrepreneurs from February 1, 2026, and for small VAT-exempt companies from April 1, 2026. This is a challenge that requires proper preparation, but also an opportunity to streamline invoicing processes and document management.

Don’t wait until the last minute! As FA partnerP, we are ready to support you in the KSeF adaptation process. We offer comprehensive advice, assistance in selecting and implementing appropriate IT solutions, and training for your employees. Contact us to discuss your company’s individual needs and plan an effective implementation!

Month: July 2025

KSeF from 2026: all about the National e-Invoicing system