National e-Invoicing System (KSeF) in Poland vs. e-Invoicing in Germany: key differences and challenges for companies

KSeF vs e-invoicing in Germany is an important topic for companies operating across borders, corporate groups, subsidiaries and businesses working with contractors in both Poland and Germany. Both countries are introducing mandatory electronic invoicing, but they are doing so in different ways. Poland uses a central tax administration platform, the National e-Invoicing System (KSeF), while Germany is developing a model based on structured invoice formats and document exchange between transaction parties.

This difference is not only technical. In practice, it affects invoice issuance, receipt of purchase invoices, archiving, approval workflows, ERP integration and tax responsibility. Companies operating in both jurisdictions should therefore treat the National e-Invoicing System (KSeF) in Poland and the German e-invoicing model as two separate operational and tax projects, rather than as one universal European standard.

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E-invoicing in Poland and Germany: the same direction, different models

Both Poland and Germany are moving towards the digitalisation of VAT settlements. The objective is similar: to reduce manual document processing, improve data quality, automate accounting and strengthen tax control. The differences arise in how the systems are organised.

In Poland, mandatory e-invoicing operates through the National e-Invoicing System (KSeF). From 1 February 2026, the obligation applied to the largest taxpayers whose gross sales value in 2024 exceeded PLN 200 million. From 1 April 2026, the second group of businesses joined the system, covering in principle the remaining taxpayers required to issue invoices KSeF. This means that KSeF is no longer only a future implementation project, but a current element of everyday invoicing and VAT settlements in Poland. The Ministry of Finance has also indicated that no penalties will be imposed in 2026 for errors made when using KSeF.

In Germany, the definition of an electronic invoice in B2B transactions changed from 1 January 2025. A simple PDF invoice sent by e-mail is no longer treated as an e-invoice under the new rules, because it does not contain a structured format enabling automated processing. However, German regulations provide transitional periods for invoice issuers, and the current model does not require every invoice to be sent through one central state platform.

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The key difference: central KSeF in Poland vs Germany’s e-invoice exchange model

The most practical difference is that Poland’s National e-Invoicing System is a state platform through which the invoice passes, while German B2B e-invoicing focuses on ensuring that the invoice is issued, sent and received in the correct structured format.

In Poland, a company must have a process prepared for handling invoices within KSeF. This means determining, among other things:

• who in the organisation is authorised to issue and receive invoices;
• how the financial and accounting system communicates with KSeF;
• how validation errors are handled;
• how the moment of invoice issuance is identified;
• how the purchase invoice workflow operates after an invoice is downloaded from KSeF;
• how business continuity is maintained in emergency and transitional modes.

In Germany, the key requirement is the ability to receive and process invoices compliant with the EN 16931 standard. Acceptable formats include XRechnung and ZUGFeRD, while German regulations do not currently impose one mandatory transmission channel for B2B e-invoices. An invoice may be transmitted, for example, by e-mail, via an interface, through a portal or by another agreed method of data exchange.

Companies operating in Poland and Germany should analyse e-invoicing not only from a technical perspective, but also from an accounting and tax perspective. getsix® supports businesses in this area through accounting in Polandand tax advisory in Poland, helping them organise financial processes in line with local requirements.

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KSeF and German e-invoicing: a practical comparison

Area	Poland: National e-Invoicing System (KSeF)	Germany: B2B e-invoicing
System model	Central tax administration system	Model based on structured formats and exchange between transaction parties
Key element	Issuing the invoice in KSeF and assigning a KSeF number	Invoice compliance with a format enabling automated processing
Status of obligation	Obligation introduced in stages from 1 February 2026; from 1 April 2026 it covers, in principle, the second group of businesses	From 1 January 2025, businesses must generally be ready to receive structured e-invoices, with transitional periods for issuance
Format	Polish structured invoice schema	EN 16931, including XRechnung and ZUGFeRD
PDF as an invoice	As a rule, it does not replace a structured invoice in KSeF where the obligation applies	A standard PDF is not an e-invoice under the new rules
Exchange channel	KSeF as the central channel for invoices covered by the obligation	No single mandatory channel for B2B; different transmission methods are possible
Accounting impact	Need to integrate with KSeF and reorganise document workflows	Need to handle structured formats and archiving in line with German requirements
Implementation risk	Validation errors, authorisations, ERP integration, receipt of purchase invoices	Format, communication channel, recipient readiness, compliance with transitional periods

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Mandatory National e-Invoicing System (KSeF) in practice: what companies in Poland must consider

From a business perspective, the National e-Invoicing System (KSeF) is now an operational obligation, not only a planned regulatory change. The obligation applied to the largest taxpayers from 1 February 2026, while the second group of businesses joined the system from 1 April 2026.

In 2026, transitional relief measures are also important. According to information from the Ministry of Finance, no penalties will be imposed in 2026 for errors made when using KSeF. In addition, special arrangements are provided until the end of 2026 for taxpayers whose monthly sales documented by invoices do not exceed PLN 10,000 gross.

For companies, it is also important that KSeF does not affect only the accounting department. The system has an impact on sales, purchasing, payments, debt collection, customer service, contractor master data management and document approval processes. In many organisations, internal procedures and employee authorisations had to be updated, and the key priority now is to monitor the correctness of day-to-day use of the system.

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E-invoicing timeline in Germany

German regulations introduce mandatory B2B e-invoicing gradually. From 1 January 2025, businesses in Germany must generally be prepared to receive electronic invoices in a structured format. At the same time, transitional periods are available for invoice issuers, meaning that in 2025 and 2026 other types of invoices, including paper invoices and certain electronic formats, may still be used under the conditions set out in the regulations.

For issuers whose turnover in the previous year did not exceed EUR 800,000, the transitional period may continue until the end of 2027. Certain EDI procedures may also continue to be used until the end of 2027 if the transitional requirements are met. Only after these transitional periods end will the use of e-invoices become fully mandatory for transactions between German businesses covered by the regulations.

It is also important to distinguish the scope of the German rules. They apply primarily to transactions between domestic businesses. A domestic business includes, among others, an entity with its registered office, management or a participating permanent establishment in Germany. VAT registration in Germany alone, without this type of local presence, does not necessarily mean that the business must issue e-invoices under the domestic B2B model.

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A PDF is not enough — but the consequences differ

In both countries, companies must move away from the assumption that an electronic invoice is simply a PDF file sent by e-mail. The practical consequences, however, are different.

In Poland, an invoice covered by the National e-Invoicing System (KSeF) obligation must be correctly issued in the system. For companies, this means that invoice data must be checked before the document is submitted. An error in the structure, buyer data, VAT rates or other fields may result in the document being rejected by the system or require the process to be corrected.

In Germany, a standard PDF also no longer meets the definition of an e-invoice from 2025. However, it may still be used as another type of invoice during transitional periods, provided that the regulations allow this and the relevant conditions are met. In the target model, businesses must be able to handle structured formats such as XRechnung or ZUGFeRD.

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Why companies operating in Poland and Germany should not implement one oversimplified solution

For international groups, it is natural to look for one e-invoicing solution for several countries. This may be justified from an IT perspective, but it should not lead to oversimplification of legal and tax requirements.

A company operating in Poland and Germany must answer several separate questions:

• whether the Polish entity is subject to the National e-Invoicing System (KSeF) obligation;
• whether the German company or permanent establishment participates in transactions covered by the German B2B e-invoicing obligation;
• whether the ERP system supports both the Polish KSeF structure and formats compliant with EN 16931;
• whether tax data can be correctly mapped for both jurisdictions;
• whether archiving meets local requirements;
• whether the purchase invoice approval process does not delay cost posting or VAT deduction;
• whether the sales department knows when an invoice may be issued outside the standard process and when this is not permitted.

In practice, the best implementation solutions combine a central IT architecture with local tax control. This means that a group may use one ERP system or one document workflow platform, but process configuration should reflect the local requirements of Poland and Germany.

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The biggest challenges for businesses

1. ERP and financial accounting system integration

The National e-Invoicing System (KSeF) requires technical readiness on the side of sales and accounting systems. Invoice data must be correctly mapped to the required structure, and the system should handle KSeF responses, the invoice identification number and error scenarios.

In Germany, the focus is on structured formats and the ability to process them. The recipient should be able to read, store and transfer invoice data in a way that allows it to be used in accounting.

2. Authorisations and responsibility within the organisation

E-invoicing implementation requires a clear division of responsibilities. This is particularly important in companies where invoices are issued by several departments or locations. Businesses need to determine who may issue invoices, who approves corrections, who monitors errors and who is responsible for receiving purchase invoices.

In KSeF, authorisation management is one of the central elements of a properly functioning process. In Germany, it is more important to define invoice receipt channels and rules of cooperation with contractors.

3. Contractor data and master data quality

E-invoicing reduces tolerance for errors in data. An outdated identification number, incorrect contractor name, wrong address or incorrect transaction classification may cause problems with issuing, posting or automatically processing an invoice.

Companies should review contractor master data, especially in corporate groups, shared service centres and businesses selling to multiple countries.

4. Purchase invoice workflow

In many companies, the e-invoicing project begins on the sales side, but the greatest difficulties arise on the purchasing side. Invoices must be received, assigned to the correct purchase order, approved, posted and included in payment processes.

In Poland, purchase invoices are downloaded from the National e-Invoicing System (KSeF) in a process that should be integrated with accounting and cost control. In Germany, the key issue is to receive the invoice through the agreed channel and process the structured data correctly.

5. Employee training and communication with contractors

The change is not limited to the tax department. Employees in sales, purchasing, customer service and administration should understand how the rules for issuing and receiving invoices have changed. Communication with contractors is also necessary, especially regarding invoice exchange channels, formats and data required on invoices.

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KSeF and German e-invoicing: relevance for foreign companies

For foreign companies operating in Poland or Germany, it is particularly important to determine whether their obligations arise from local presence, tax registration, a fixed establishment, buyer status or the nature of the transaction.

In Poland, the National e-Invoicing System (KSeF) may be important for foreign entities with a fixed establishment or those carrying out transactions subject to Polish invoicing requirements. In Germany, VAT registration alone, without a registered office, management or a participating permanent establishment, does not necessarily mean that the business is required to issue e-invoices under the domestic B2B model, but each case should be assessed individually.

This is why international companies should combine technical analysis with tax analysis. Implementing an IT tool alone does not guarantee compliance if the scope of obligations in each jurisdiction has not first been properly determined.

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How to adapt your company to KSeF and German e-invoicing

Businesses should start with a review of their current invoicing processes. In practice, it is worth analysing:

• what types of invoices are issued in the company;
• which systems generate invoice data;
• how the purchase invoice workflow operates;
• who approves corrections and non-standard invoices;
• what contractor data is stored in the system;
• whether the company uses EDI, contractor portals or document workflow tools;
• whether document archiving meets local requirements;
• whether the accounting team has procedures for system errors.

For Polish entities, it is particularly important to continuously monitor integration with the National e-Invoicing System (KSeF) and respond quickly to validation errors, authorisation issues and irregularities in purchase invoice workflows. Because the system is already mandatory for a broad group of businesses, companies should focus not only on launching the solution, but also on stabilising processes, controlling data quality and documenting internal procedures.

For German entities, the focus should be on the ability to receive e-invoices, support structured formats, archive documents correctly and agree exchange channels with contractors.

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The role of accounting and tax advisory in an e-invoicing project

E-invoicing implementation is a project at the intersection of technology, accounting and taxation. The IT department can provide system integration, but accounting and tax advisory teams should confirm whether invoice data, correction processes, the moment of invoice issuance, archiving and VAT settlement are compliant with local requirements.

Companies that need support in adapting their accounting processes to new obligations can use getsix® accounting services in Poland. For issues involving VAT, invoicing obligations and cross-border compliance, getsix® also provides tax advisory in Poland.

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Summary: what should companies pay attention to?

The National e-Invoicing System (KSeF) in Poland and Germany’s e-invoicing system have a common objective, but they differ in structure. Poland uses a central system in which the invoice is issued through KSeF. Germany is developing a model based on structured e-invoice formats and document exchange between businesses.

For companies, this means that compliance must be approached locally. A general declaration of e-invoicing readiness is not enough. Businesses need specific procedures, system tests, data controls, assigned responsibilities and accounting processes adapted to the requirements of the relevant country.

The key conclusions for businesses are:

• The National e-Invoicing System (KSeF) and German e-invoicing are not the same system.
• A standard PDF is no longer sufficient as the target model for electronic invoicing.
• Poland uses the central KSeF platform as the main channel for invoices covered by the obligation.
• Germany requires readiness to receive and process structured invoices.
• Companies operating in both countries should treat implementation as a tax, accounting and technology project.
• The biggest risks concern data quality, ERP integration, purchase invoice workflows and incorrect assessment of the scope of obligations.

A well-planned e-invoicing implementation can not only reduce tax risks, but also improve financial processes, shorten document posting times and strengthen control over business data. Companies should therefore treat the National e-Invoicing System (KSeF) and German e-invoicing not only as regulatory obligations, but also as an opportunity to organise accounting and tax processes more effectively.

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