Poland’s KSeF System: What the Mandatory B2B eInvoicing from 2026 Means for International Trading Partners
Last month, I received a call at Peppol.nu from a Dutch logistics service provider who has been active in Poland for years. “We have a distribution center in Wrocław,” the director told me, “and we heard something about a new einvoicing system that’s becoming mandatory. But no one on our team knows enough about einvoicing to understand all the information. Does this apply to us as well?”
It’s a familiar question. Poland is implementing one of Europe’s most ambitious einvoicing mandates from February 2026 through the KSeF system (Krajowy System eFaktur). For Dutch companies doing business with Polish partners, this development raises important questions. Think of manufacturing companies with facilities in Katowice, IT companies supplying software to Warsaw, construction companies involved in infrastructure projects, or consultancy firms advising Polish SMEs.
What’s special about Poland’s approach is that the country is choosing a centralized clearance model, comparable to what Italy has been using since 2019. This means that every invoice must go through a government platform, unlike the decentralized Peppol models that Belgium, France, and the Netherlands use. This has far-reaching consequences for international companies.
The Facts at a Glance
From February 1, 2026, Poland will start mandatory implementation of electronic invoicing through the national KSeF platform. This will happen in phases across three implementation stages. Large enterprises with annual revenue exceeding 200 million PLN (approximately €46 million) in 2024 must be fully compliant from February 2026. Two months later, on April 1, 2026, all other VAT-registered businesses must switch to KSeF for all B2B transactions. Micro-enterprises with monthly invoicing below 10,000 PLN (approximately €2,350) get a reprieve until January 1, 2027.
A crucial nuance is the grace period for sanctions. Until December 31, 2026, no penalties will be imposed for errors in using KSeF, giving businesses extra time to organize their processes. But note: this doesn’t mean the system is optional during this period.
Additionally, there’s an important receiving obligation that’s often overlooked. From February 2026, all Polish companies—regardless of their revenue—must be technically capable of receiving electronic invoices through KSeF, even if they’re not required to send them until later. A small company not required to start sending until April 2026 must still be able to receive from February.
What is the KSeF System?
The Krajowy System eFaktur (KSeF) is a free, government-managed central platform for exchanging electronic invoices. The system has been available for voluntary use since January 2022 and is now becoming mandatory for all B2B transactions.
The core functionality revolves around centralized validation: every invoice is validated by the government platform before it goes to the recipient. Each approved invoice receives a unique KSeF identification number. The system automatically archives all invoices for ten years, relieving businesses of their own archiving obligations. Real-time compliance provides immediate checks on technical correctness and consistency. The big advantage is integration with VAT returns: based on registered invoices, returns can be pre-populated. Another attractive benefit for users is the shortened VAT refund time, which drops from sixty to forty days.
The clearance process works as follows. The sender generates an invoice in FA(3) XML format and sends it to KSeF via an API or the government’s free Taxpayer Application. The KSeF platform then performs technical checks and format validations. Upon approval, a unique KSeF ID is assigned within seconds to minutes. The invoice is then made available to the recipient in the KSeF system and the sender receives notification with the KSeF reference number. Simultaneously, automatic reporting occurs to the tax authorities.
The FA(3) Format: Poland’s Own Standard
Unlike most European countries that have adopted the EN 16931 standard, Poland uses its own national invoice format: FA(3), the successor to FA(2) which was used during the voluntary phase.
The FA(3) format is XML-based and contains structured data, but it is explicitly not compliant with the European EN 16931 standard. Poland deliberately chose its own specifications that contain more extensive fields than the EU standard requires. From 2026, documents can be added as attachments to invoices, which wasn’t possible before. QR codes are used for offline verification and identity verification, which can be printed on paper or PDF versions of the einvoice.
What does this mean in practice? Companies already using einvoicing for other European markets, for example via Peppol, cannot directly use their existing systems for Poland. A separate integration with KSeF is needed, including conversion to the FA(3) format. This is an important consideration for international companies hoping to reuse their existing einvoicing infrastructure.
The Offline24 Mode: Flexibility During Connectivity Issues
A unique feature of the KSeF system is the Offline24 functionality. This provides a safety net for businesses that temporarily cannot make a real-time connection with the central platform.
During connectivity problems, an invoice can be issued offline in PDF format or on paper. The invoice then contains two QR codes: one for verification of invoice validity in KSeF and one for confirmation of the supplier’s identity. The crucial obligation is that the invoice must still be sent to KSeF within one business day. After validation, this invoice also receives a regular KSeF ID.
Originally, businesses had to request permission in advance to use Offline24. This has been postponed: until the end of 2026, everyone can use this mode voluntarily without prior approval. From 2027, prior approval will be required.
The practical application is especially valuable for companies in areas with limited internet connectivity, mobile workers such as truck drivers and field service employees, emergency situations during system failures, and during the transition period while systems are being integrated.
When Does the KSeF Obligation Apply Exactly?
This is the most frequently asked question by international companies. The answer is more nuanced than with other European mandates.
The obligation applies to all VAT-registered businesses with a registered seat in Poland. Foreign businesses with a fixed establishment in Poland also fall under the obligation, but only if that fixed establishment is involved in the supply.
The obligation does not apply to foreign businesses without a seat or fixed establishment in Poland. Foreign businesses with a fixed establishment that is not involved in the specific transaction also fall outside the scope. Furthermore, B2C transactions are exempt, unless both parties explicitly agree to use KSeF. Invoices under OSS/IOSS schemes and toll road cards and similar tickets also fall outside the mandatory scope.
A special regulation applies to invoices to foreign customers. For export or intra-community supply, the invoice must be entered into KSeF and receives a KSeF ID, but the foreign customer doesn’t get automatic access to the system. The Polish supplier must send the invoice separately, for example as a PDF with QR code.
Scenario 1: The Dutch Exporter Without Fixed Establishment
TechExport BV from Eindhoven supplies industrial machinery to Polskie Przemysł Sp. z o.o. in Gdańsk. TechExport has no office or personnel in Poland, but does have a Polish VAT registration for these supplies.
The reality: Foreign suppliers without a fixed establishment in Poland don’t fall under the KSeF obligation. TechExport therefore doesn’t need to send invoices via KSeF.
But—and this is the problem: Polskie Przemysł is required from February or April 2026 (depending on their revenue) to receive all invoices from Polish suppliers via KSeF. This means the Polish company must maintain two different invoice processing channels: on one hand KSeF invoices from Polish suppliers that are processed automatically with pre-populated VAT returns, and on the other hand traditional invoices from foreign suppliers like TechExport that must be processed manually.
This creates operational problems for the Polish company. They must maintain dual systems and processes, leading to increased administrative costs. Processing becomes more error-prone because there are two different workflows. VAT processing for international invoices is less efficient because it must be done manually, and this often results in longer payment terms for non-KSeF invoices because processing takes more time.
The Polish Ministry of Finance has emphasized that non-KSeF invoices during the so-called ‘grace period’ in 2026 technically remain valid for VAT deduction, but buyers may face a higher burden of proof during audits. This means concretely that more documentation may be required during audits, possible delays may occur in VAT refunds, and there’s an increased risk of questions from the tax authorities.
Some Polish companies may therefore develop a preference for suppliers who do invoice via KSeF, simply because it’s administratively simpler and legally more robust.
Scenario 2: The German Company with Fixed Establishment in Poland
Automotive Solutions GmbH from Stuttgart has a production facility in Tarnów with its own personnel, machinery, and warehouses. From this Polish establishment, they supply parts to Polish car manufacturers and dealers.
The reality: Foreign businesses with a fixed establishment in Poland are considered Polish taxpayers for transactions that go through that establishment and fall fully under the KSeF mandate.
Automotive Solutions GmbH must send all invoices via KSeF from February or April 2026 (depending on their revenue). They must integrate their ERP system in Germany with the KSeF platform, train personnel in using the system, implement the FA(3) XML format, and comply with all Polish compliance requirements.
The criterion: fixed establishment
It’s not the nationality of the parent company that determines the obligation, but the presence of a fixed establishment on Polish territory that is involved in the supply.
What is a Fixed Establishment?
According to Polish interpretation, there is a fixed establishment when there is sufficient stability of presence, an adequate structure exists in human and technical resources, and goods or services are regularly delivered from that location.
Examples of fixed establishments are production facilities, offices with personnel, distribution centers and warehouses, service centers, and permanent representatives with decision-making authority. On the other hand, temporary projects of a few months don’t constitute a fixed establishment, nor do incidental presence, mere storage without further activities, or agents without representation authority.
However, there is an important legal controversy. The European Commission granted Poland a derogation (deviation) from the VAT Directive in 2022 to introduce mandatory einvoicing, but this derogation was explicitly limited to entities with their seat in Poland.
The Polish law, however, extends the obligation to foreign companies with a fixed establishment. A Polish administrative court ruled in October 2024 that this extension may possibly fall outside the scope of the EU permission.
This creates legal uncertainty for foreign companies with fixed establishments, their Polish customers, and advisors and accountants guiding these parties.
The Polish Ministry of Finance has announced it will provide additional clarification on the criteria for fixed establishment, but this has not been published at the time of writing.
Scenario 3: The French Consultant Without Fixed Establishment
Conseil Stratégie SARL from Paris provides management consultancy to Polish financial institutions. The company has a Polish VAT registration but no physical presence—consultants fly in for projects and work from hotels or client offices.
The reality: No fixed establishment means no KSeF obligation. Conseil Stratégie can continue invoicing as usual via PDF or other traditional methods.
But: Their Polish clients are confronted with the dual administration problem: KSeF invoices from Polish suppliers and traditional invoices from international partners like Conseil Stratégie.
The strategic opportunity:
For ambitious consultancy firms like Conseil Stratégie, voluntary adoption of KSeF can provide a competitive advantage. You relieve the administrative burden of your Polish clients, which strengthens customer relationships. KSeF invoices are generally processed faster, resulting in faster payments. It shows a professional image by demonstrating commitment to the Polish market. If Poland is your main market, you’re prepared for possible future extensions of the obligation. Finally, you differentiate yourself from advisors who remain traditional, which provides a concrete competitive advantage.
Practical implementation requires several steps. You can contract with a Polish accountancy firm or service provider that facilitates KSeF access. Alternatively, you can invest in your own API integration with the KSeF platform. However, take into account the costs of implementation and maintenance, because although the platform itself is free, there are costs associated with technical integration.
KSeF versus Peppol: Fundamental Differences
A frequently asked question: “Can I use my existing Peppol connectivity for Poland?”
The answer is unfortunately: no, not directly.
Architectural Differences:
| Peppol | KSeF | |
| Model | Decentralized 4-corner model | Centralized clearance model |
| Validation | By the Serviceprovider | By the government platform |
| Standard | EN16931, UBL/CII, Peppol Bis 3 | FA(3) xml |
| Scope | International | National |
| Access | Via a Peppol Access Point of choice | Via the national government platform |
| Routing | Peer-to-peer between Access Points (Service providers) | Always via a central hub |
| Archiving | By the service provider or the software package. | By the government |
What This Means for International Companies:
If you already have Peppol connectivity for Belgium, France, or other European markets, you cannot reuse this infrastructure for Polish clients. You need a separate integration with the KSeF platform specifically, including conversion to the FA(3) format, Polish authentication mechanisms, and Polish validation rules.
Exception for B2G: For Business-to-Government transactions in Poland, there is the PEF platform (Platforma Elektronicznego Fakturowania) that supports Peppol BIS 3.0. This means suppliers to Polish government institutions can use their existing Peppol connectivity.
However, from 2026, government institutions can also be reached via KSeF, giving businesses the choice between PEF/Peppol for B2G transactions with existing systems, or KSeF with FA(3) for uniform processing of both B2B and B2G.
The expectation is that many companies will consolidate to KSeF for both B2B and B2G to have one system.
European Context: Poland’s Unique Choice
Poland’s approach deviates significantly from the direction most other EU countries are choosing.
Comparison with Other Countries:
Versus Italy: Poland follows the Italian model of centralized clearance via the SDI system. Both countries have government-configured central platforms, real-time validation of all invoices, their own national formats (FatturaPA for Italy, FA(3) for Poland), and strict control over VAT compliance.
Versus Belgium: Belgium chooses the exact opposite: a fully decentralized Peppol 4-corner model with free choice of service provider, no central government validation upfront, use of the international standard EN 16931, and market-driven competition.
Versus France: France uses a hybrid model with decentralized PDPs (Partner Dematerialization Platforms), a central PPF as data hub, support for both EN 16931 and Peppol, and nearly one hundred certified providers businesses can choose from.
Strategic Considerations:
Poland’s choice for centralization has both advantages and disadvantages. On the positive side: maximum control over VAT compliance and fraud prevention, consistent validation and quality assurance, a free platform available to all businesses, faster VAT refund through automatic reporting, and a uniform system for everyone.
On the other hand, there are also disadvantages. Vendor lock-in occurs with one government platform without alternatives. Flexibility and room for innovation are limited. The system is not interoperable with international systems like Peppol. There’s a risk of technical problems with central infrastructure, which affects all users. Finally, there may be less competitive pressure on service quality because there’s no market competition between different platforms.
Practical Preparation: What Needs to Happen Now?
For Companies with Polish Establishment
The first step is determining which implementation phase you fall into. For phase 1, which starts on February 1, 2026, the obligation applies if your revenue in 2024 exceeded 200 million PLN. Phase 2 starts on April 1, 2026 and applies to all other businesses. Micro-enterprises with less than 10,000 PLN per month fall under phase 3 from January 1, 2027.
Analyze your current systems thoroughly. Which ERP or accounting system do you currently use? Does it already support the FA(3) XML format? Is there an existing KSeF integration available from your software supplier? And what adjustments are needed to become compliant?
Then you must choose an implementation strategy. You have three main options. First, you can use the government’s free Taxpayer Application. This works directly via the government platform, is suitable for small volumes, but offers limited automation because you must enter invoices manually one by one.
The second option is full API integration. This ensures complete automation and is suitable for medium to large invoicing volumes. It does require technical expertise and integration with your existing systems.
The third option is working through a third-party service provider. This is a middle solution that offers extra functionality on top of the basic platform, including support and guidance. Costs vary per provider, and you need less technical knowledge in-house.
Register timely for a KSeF certificate. From November 1, 2025, these access certificates can be requested. They’re valid for two years and renewable. You need them for authentication in the system, and they replace or supplement token-based access.
Test extensively in the demo environment. The KSeF 2.0 test environment has been available since September 2025, and the pre-production DEMO environment since October 15, 2025. Use these for complete system integration testing. Especially validate whether your FA(3) format is correct and whether API communication works properly.
Train your personnel on time. This applies to accounting and finance teams, IT departments, and all users who will work with the system. Note especially that the KSeF interface is entirely in Polish, which can be an extra challenge for international teams.
For large companies in phase 1, the timeline is tight. In November 2025, you request certificates and start intensive testing. December 2025 is used for finalizing systems and final tests. January 2026, you run an internal pilot with a select number of invoices. On February 1, 2026 is the official go-live, and from then compliance is mandatory.
For companies in phase 2, there’s slightly more time, but postponement is not advisable. The transition takes more time than most companies estimate, and you don’t want to end up in the rush of Q1 2026 when all phase 1 companies go live.
For Foreign Suppliers to Polish Companies
Start with a strategic evaluation of your position. Assess your Polish customer portfolio: how many customers do you have in Poland? What’s the total invoice volume to this market? Are these strategic, long-term relationships or incidental customers? And what’s the current administrative burden of your Polish invoicing?
Then analyze the business case for voluntary adoption. On the cost side are implementation costs as a one-time investment, possible monthly costs if you work through a service provider, internal time for setup and training, and maintenance and updates. On the benefits side are stronger customer relationships through administrative efficiency, possibly faster payments, a competitive advantage over suppliers who remain traditional, and future-proofing. As a rule of thumb: if you send more than fifty invoices per year to Poland and these are strategic customers, voluntary adoption can be profitable.
Communicate proactively with your Polish customers. An example: “Dear customer, as you probably know, Poland is introducing mandatory einvoicing from February 2026 via the KSeF system. Although we as a foreign supplier are not required to invoice via KSeF, we understand this may mean administrative complexity for you. We’re currently investigating the possibility of voluntarily connecting to the KSeF system, so you can process all your invoices uniformly. We’ll keep you informed of our decision. Do you have questions about this, or do you have a preference? Let us know.”
If full KSeF integration is too complex, consider a hybrid approach. You can enter into a partnership with a Polish accountancy firm that enters invoices into KSeF on your behalf. Or you use specialized service providers that convert from your invoice format to FA(3). You can also develop a custom solution together with large Polish clients that works for both parties.
For Accountants and Advisors
The KSeF transition creates substantial demand for professional guidance. There are opportunities in implementation support, system integrations, training and workshops, compliance advice, and ongoing support.
Position your services around five core areas. First, gap analyses comparing the current state with KSeF requirements. Second, implementation projects with end-to-end guidance from preparation to go-live. Third, managed services for continuous support after going live. Fourth, training from basic to advanced level for different target groups. Fifth, compliance checks through periodic audits to ensure compliance.
The ‘Grace Period’ Strategy: To Wait or Not to Wait?
A frequently asked question is whether companies can simply wait until 2027, since there are no fines in 2026 anyway. The short answer: that’s not a smart plan.
Although there are formally no financial sanctions until January 1, 2027, there are consequences of late adoption. The first risk concerns the increased audit burden for customers. Non-KSeF invoices are legally valid but less robust. Buyers may have to submit additional documentation during audits and possible delays may occur in VAT refunds for your customers. This ultimately damages your business relationships.
Second, reputational damage occurs. Polish companies may start doubting non-KSeF invoices and wonder why a supplier doesn’t use the system. There’s a perception of lagging behind or being non-compliant.
Operational problems form the third risk. There will be a rush in the fourth quarter of 2026 when everyone implements at once. This creates a shortage of implementation capacity at service providers, costs rise due to time pressure, and the risk of errors in hasty implementation increases.
Finally, you miss out on benefits. You’re not entitled to the shortened VAT refund time in 2026. You continue using manual processes instead of automation. You miss the learning experience during the grace period. And you miss early adopter insights that can be valuable.
Early adoption between the fourth quarter of 2025 and the first quarter of 2026, on the other hand, offers substantial benefits. You have plenty of time for testing and problem-solving without time pressure. There’s sufficient availability of implementation expertise. You can learn during the grace period without sanction risk. You already benefit from the shortened VAT refund time in 2026. You strengthen your position with Polish clients by being progressive. This provides a competitive advantage. And you can go through the implementation calmly without stress.
The recommendation is therefore clear: start preparation in the fourth quarter of 2025, go live in the first quarter of 2026 during the ‘grace period’, and optimize your processes throughout 2026. Then you’re fully prepared and ready when sanctions take effect in January 2027.
International Trade Flows and Dutch Context
The Netherlands and Poland have strong trade dynamics. In 2024, bilateral trade amounted to more than €35 billion, with the Netherlands being both an important exporter to Poland and using Poland as a production location.
The Dutch presence in Poland is substantial with more than 1,200 Dutch companies active in the country. There’s concentration in specific sectors. Transport and logistics forms an important pillar with Polish trucking and Dutch forwarding companies. In manufacturing, Dutch companies are active in electronics, automotive suppliers, and food products. In retail, well-known names like Albert Heijn (via Ahold Delhaize) and Action are present. ICT and Business Services include shared service centers and IT outsourcing. In construction and infrastructure, companies like Ballast Nedam and BAM are active in civil engineering.
Polish presence in the Netherlands is also significant. The Polish transport sector with trucking and logistics plays a major role. In construction and engineering, many Polish companies are active. The agri-food sector includes product processing by Polish enterprises. Additionally, producers like Wielton and Solaris Bus & Coach have manufacturing activities in the Netherlands.
For most Dutch companies with Polish activities, there’s a clear separation. Companies with a Polish establishment such as production facilities, distribution centers, offices with personnel, or service centers fall under full KSeF compliance and are required to participate. Companies without a Polish establishment but with Polish customers must evaluate voluntary participation, communicate proactively with customers, and prepare a hybrid solution for the transition period.
The Peppol.nu Recommendation: Pragmatic Preparation
For Dutch companies active in Poland, our recommendation depends on the situation.
Companies with a Polish establishment must take action now. Start in the fourth quarter of 2025 with a gap analysis and system selection. Carry out implementation and testing in the first quarter of 2026. Go live in the second quarter of 2026 and start optimizing. Use the second half of 2026 for fine-tuning during the grace period.
For companies without a Polish establishment, the situation requires strategic evaluation. If the Polish market represents more than twenty percent of your revenue, seriously consider KSeF adoption. At five to twenty percent revenue, evaluate the full business case. Below five percent, you can continue invoicing traditionally for now, but do monitor developments. In all cases, communicate transparently with your customers about your choice. Offer alternatives such as detailed PDFs and additional documentation. Monitor feedback from Polish customers throughout 2026 to see if adjustment is needed.
Advisors and consultants can position themselves as KSeF experts. Actively follow the webinars of the Polish Ministry of Finance. Invest in training your team so you build solid expertise. Build a network with Polish accountants for knowledge sharing and collaboration. Develop a standard implementation methodology that you can apply consistently.
Timeline and Critical Moments
Present – October 2025:
- KSeF 2.0 API test environment available
- Pre-production DEMO environment launched
- “Wednesdays with KSeF” webinars by Ministry of Finance
November 1, 2025:
- Certificates can be requested
- MCU Module (permissions management) available
- Offline24 approval possible (but not mandatory until end of 2026)
December 2025:
- Final test period for large companies
- Finalization of system integrations
January 1, 2026:
- Attachments to invoices possible
- Final preparations Phase 1 companies
February 1, 2026:
- GO-LIVE PHASE 1: Large companies (>200M PLN revenue) mandatory
- Receiving obligation for ALL companies
April 1, 2026:
- GO-LIVE PHASE 2: All other companies mandatory
August 1, 2026:
- Bank transfer references must contain KSeF ID
December 31, 2026:
- End of grace period for invoices from cash registers
- End of sanction-free period (note for 2027)
January 1, 2027:
- Sanctions in effect for non-compliance
- GO-LIVE PHASE 3: Micro-enterprises
- Offline24 requires prior approval
From Challenge to Opportunity: The Strategic Perspective
For Polish companies, KSeF can be more than a compliance obligation. It offers opportunities for administrative efficiency through automated processing, faster cash flow with forty days instead of sixty days VAT refund, fewer errors through standardized validation, better data analysis through structured information, and lower audit intensity thanks to pre-populated returns.
For international companies, the Polish market remains attractive. Poland has a strategic location in Central Europe, a large and growing economy, a qualified workforce, competitive costs, and the advantage of EU membership.
KSeF shouldn’t be a reason to avoid Poland. It does require conscious strategic choices, timely preparation, good advice, and possibly investment in systems.
Start Your Preparation
For companies with Polish establishment: Start preparing NOW. The time until February 2026 may seem long, but system integration, testing, and training take months. Don’t wait until the last moment.
For international suppliers: Evaluate your position and communicate with your Polish customers. Voluntary KSeF adoption can distinguish you from competitors and strengthen your relationships.
For both groups: Don’t see KSeF as a bureaucratic burden, but as part of Poland’s digital transformation. Countries that invest early in digital VAT systems (like Italy with SDI) have lower fraud and more efficient tax collection. This ultimately benefits all honest entrepreneurs.
Need Support with Poland’s KSeF Implementation?
Visit Peppol.nu for more information about international einvoicing mandates and how they relate to each other. Check our overview of Peppol suppliers to see which providers also offer support for Poland.
For specialist guidance with complex international einvoicing strategies, you can contact Solventis.
Stay informed about developments around Poland’s KSeF system and other European einvoicing mandates via Peppol.nu.
Frequently Asked Questions About KSeF
Can I use my Peppol connectivity for Poland? No, not directly. KSeF uses its own FA(3) XML format that’s not compatible with Peppol’s EN 16931 standard. You need a separate integration. You can use Peppol for Polish B2G transactions via the PEF platform.
Must I as a Dutch supplier without Polish establishment use KSeF? No, the obligation only applies to companies with a seat or fixed establishment in Poland. However, voluntary participation can offer benefits for your Polish customer relationships.
What happens if I make mistakes during the grace period in 2026? Until December 31, 2026, no fines are imposed for KSeF-related errors. This gives businesses time to learn and optimize processes.
How do I know if my company has a fixed establishment in Poland? This is currently a gray area. General criteria are: sufficient stability of presence, adequate structure (personnel/resources), and regular deliveries. The Polish Ministry of Finance will publish further guidance.
Can I continue sending invoices if the KSeF system is offline? Yes, via the Offline24 mode. You send the invoice offline (with two QR codes) and upload it to KSeF within one business day once the connection is restored.
Is the KSeF system free? Yes, the platform itself is free. However, costs may arise from integrating your ERP system, using third-party service providers for extra functionality, implementation and training, and ongoing maintenance and support.
What’s the difference between KSeF and Peppol? KSeF is a centralized national platform with clearance model, Peppol is a decentralized international network. KSeF uses FA(3) XML, Peppol uses EN 16931-compliant formats (UBL/CII).
Must I also send my outgoing invoices to foreign customers via KSeF? Yes and no. The invoice must be entered into KSeF and receives a KSeF ID (for reporting to tax authorities), but the foreign customer doesn’t get access to KSeF. You send the invoice separately (for example as PDF with QR code).
What happens after 2026 with companies that haven’t transitioned yet? From January 1, 2027, sanctions take effect. These can amount to up to one hundred percent of the VAT amount on the invoice, or 18.7 percent of the total amount for invoices without VAT mention.
Can I simply wait until 2027 because there are no fines in 2026? Technically yes, but this is not advisable. Non-KSeF invoices during 2026 can lead to increased audit burden for your customers, reputational damage, and operational problems. Early adoption actually offers advantages.
How does KSeF relate to the European ViDA directive? KSeF is Poland’s national implementation, anticipating the EU-wide ViDA requirements (from 2030). However, ViDA prescribes EN 16931 compliance, while Poland uses FA(3). Poland will possibly need to make adjustments to become fully ViDA-compliant.
What should I do if my ERP system doesn’t support FA(3)? You have three options. First, you can purchase a software upgrade or add-on from your ERP supplier. Second, you can use middleware or a conversion tool that converts your format to FA(3). Third, you can engage a third-party service provider that does the conversion for you. Large ERP systems like SAP, Microsoft Dynamics, and Odoo now have KSeF modules available.
Sources
- Polish Ministry of Finance – KSeF 2.0 Manual
- European Commission – eInvoicing in Poland
- Council Implementing Decision (EU) 2022/1003
- VATCalc – Poland B2B KSeF e-invoicing
- Global VAT Compliance – Poland mandatory B2B e-invoicing 2026
- EDICOM Global – Poland B2B Electronic Invoicing Mandatory
- Maros VAT – E-invoicing in Poland: KSeF Complete Guide
- The Invoicing Hub – Understanding Poland’s 2026 B2B e-invoicing requirement
- Tradeshift – Poland’s B2B e-Invoicing mandate
- Pagero – E-invoicing compliance in Poland
- Poland Accounting – Foreign contractors and fixed establishment in KSeF
- RSM Poland – Obligation of using structured invoices (KSeF)
- CRIDO – Receiving invoices in Polish KSeF system from February 2026
