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GrokKey points at a glance:
- The KSeF system becomes mandatory in Poland from 1 February 2026, but only for taxpayers established on Polish territory.
- Businesses not established in Poland are not subject to the obligation but may use the system voluntarily.
- Only electronic invoices in structured format issued via KSeF are recognised as compliant for businesses subject to the obligation.
- KSeF centralises the issuance, receipt and archiving of invoices for 10 years, with automatic transmission of documents.
In 2023, Poland decided to join the group of Member States making electronic invoicing mandatory. In this context, the KSeF system represents a major step forward in Polish tax digitalisation and VAT control.
As early as 2022, it had obtained authorisation from the European Commission to introduce this system, by way of derogation from European VAT rules. However, this authorisation includes an important limitation: taxpayers not established in Poland are excluded from the obligation.
It should be noted that the Polish electronic invoicing system had already been operating on a voluntary basis since 2022. Businesses could therefore use it optionally before it became mandatory.
Electronic invoicing, originally scheduled for 2024, was postponed, mainly due to necessary technical adjustments. The KSeF system finally became mandatory on 1 February 2026, exclusively for taxpayers established in Poland. Non-established businesses are not subject to this obligation.
This development directly concerns businesses operating under VAT in Poland and requires compliance with Polish tax obligations.
Related article:
Poland: Mandatory Electronic Invoicing from 2024
What is KSeF?
KSeF stands for Krajowy System e-Faktur. It is the national electronic invoicing system implemented in Poland.
Under this system, all taxpayers established in Poland must issue their sales invoices in a structured electronic format that complies with the technical requirements imposed by the KSeF system. This obligation applies exclusively to transactions between VAT taxpayers, i.e. B2B operations.
This fully aligns with the rules of Polish B2B electronic invoicing and European electronic invoicing practices.
It is important to distinguish between two types of electronic invoices provided for by Polish regulations:
The Structured KSeF Electronic Invoice
It is issued directly via the KSeF system and must strictly comply with the format and technical criteria defined by the tax authorities. Only this invoice meets the legal obligation applicable to businesses established in Poland.
The “Classic” Electronic Invoice
This is also an invoice issued in electronic format (PDF, EDI, etc.), but its format remains free. It can be generated from any software and according to the terms chosen by the issuer. Unlike the KSeF invoice, it does not meet the requirements of the mandatory structured system.
Only the first type constitutes a legally recognised KSeF electronic invoice under the obligation.
| Invoice Type | Format / Transmission | Meets the KSeF Obligation |
|---|---|---|
| Structured KSeF Invoice | Structured format via KSeF | Yes |
| Classic Electronic Invoice | PDF, EDI, other | No |
| Paper Invoice | Paper | No |
What is the content and structure of a KSeF invoice?
KSeF invoices must follow a very precise structured format, based on an XML schema defined by the Polish tax authorities.
This format notably includes:
- Supplier details (name, address, VAT number)
- Customer details
- Unique invoice number assigned by the system
- Date of issue and date of supply
- Invoice line details:
- Description of goods/services
- Quantities
- Unit prices
- Applicable VAT rates
- Net, VAT and gross amounts
| Element | Presence in KSeF |
|---|---|
| Invoice number | Generated by KSeF |
| Format | Structured XML |
| Signature | Not required |
| Validation | Automatically performed by the system |
What is the lifecycle of an invoice in KSeF?
The operation of KSeF is based on a well-defined process.
Here are the main steps:
- Creation of the invoice in the accounting system
- Conversion to structured KSeF format (XML)
- Transmission to the KSeF system
- Validation by the tax authorities
- Assignment of a unique identifier
- Automatic availability to the recipient
What are the objectives of the KSeF system for the Polish tax administration?
The KSeF system is not just a technical requirement. It pursues several strategic objectives for the Polish tax administration.
Among the main goals:
- Reduction of VAT fraud
Thanks to real-time access to invoicing data, the administration can detect anomalies more quickly. - Automated transaction monitoring
Since invoices are structured, they can be automatically analyzed by algorithms. - Improved tax collection
Better visibility enables more effective audits and optimizes tax revenues. - Simplification of audits
Tax inspections are facilitated through direct access to data.
What are the benefits of the KSeF system in Poland?
Automatic invoice transmission
The issuer does not need to send the invoice to the recipient: it is automatically transmitted and accessible in the recipient taxpayer’s portal.
Centralised database
KSeF is not limited to a simple invoicing tool: it also constitutes a true tax database.
Every user has online access to:
- All sales invoices issued via the system
- All purchase invoices received through the system
Long-term archiving
Invoices are kept for a period of 10 years, guaranteeing secure archiving in compliance with regulatory requirements.
What are the challenges of the KSeF system in Poland?
IT system adaptation
Businesses must adapt their internal accounting systems to meet the technical requirements of KSeF.
Strict invoice format
Only structured-format invoices sent and accepted by the system are recognised as valid by the authorities.
International invoicing
The KSeF obligation also applies to invoices issued to foreign taxpayers. The transmission method must be agreed with them.
| ✔ Advantages | ⚠ Challenges |
|---|---|
| Automatic transmission Invoices are automatically transmitted and accessible in the recipient’s portal. | IT adaptation Accounting systems must be adapted to the technical requirements of KSeF. |
| Centralised access Online consultation of all sales and purchase invoices via a single database. | Structured format Only invoices compliant with the KSeF format are valid. |
| 10-year archiving Invoices are automatically stored for 10 years. | International invoicing Agreement required with foreign partners on the transmission method. |
What sanctions are provided for in case of non-compliance?
Sanctions are provided for taxpayers established in Poland who fail to comply with the obligation.
However, their application is suspended until the end of 2026.
Non-established businesses are not subject to these sanctions.
Optimize your VAT management in Poland with ASD Taxflow
Managing VAT in Poland can quickly become complex, particularly with the introduction of the KSeF system and the strengthening of e-invoicing requirements. With ASD Taxflow, you can streamline all your tax processes and ensure your compliance.
Are foreign businesses subject to the KSeF obligation?
No.
Article 106ga §2 point 2 of the Polish VAT Code explicitly excludes taxpayers not established in Poland from the obligation.
The European decision authorising the derogation from Directive 2006/112/EC also states:
“By way of derogation from Article 218 of Directive 2006/112/EC, Poland is authorised to accept only invoices issued by taxpayers established on Polish territory in electronic form.”
Non-established businesses may continue to:
- Issue paper invoices
- Issue electronic invoices in free format
Can foreign businesses use KSeF voluntarily?
Yes.
Even though they are not subject to the obligation, businesses not established in Poland have the option of using the system voluntarily.
This enables them to:
- Issue their sales invoices via KSeF
- Receive local purchase invoices directly in the system
This is a strategic choice left to the foreign taxpayer, not a regulatory requirement.
| Company Situation | Obligation to issue via KSeF | Voluntary use possible |
|---|---|---|
| Taxpayer established in Poland | Yes (mandatory) | — |
| Taxpayer not established in Poland | No (excluded) | Yes (possible) |
| Non-established taxpayer with a permanent establishment in Poland | Yes if a permanent establishment is involved | — |
What are the best practices for achieving compliance with the KSeF system?
To effectively anticipate the KSeF requirement, companies can follow several recommendations:
| Strategic focus | Recommended actions |
|---|---|
| Anticipate technical developments | – Audit of existing systems – Identification of gaps |
| Test the system | – Use of the KSeF test environment – Validation of invoicing flows |
| Train teams | – Awareness training for accounting departments – Training on new processes |
| Collaborate with experts such as ASD Group in Poland | – Tax advisory support – Support |
As part of the rollout of the KSeF system in Poland, ASD Group supports companies in achieving compliance with electronic invoicing and VAT obligations in Poland. With our expertise in European taxation and our digital solutions, you can secure your operations and facilitate your expansion in Poland.
Secure your VAT compliance in Poland
Anticipate risks with a VAT audit and a review of your invoicing flows. Benefit from the expertise of the specialists at ASD Group to structure and secure your operations in Poland.
Sources:
- Article 218 of Directive 2006/112/EC (English PDF)
- 106ga §2 point 2 of the Polish VAT Code (Polish)
- ksef.podatki.gov.pl (Polish)
FAQ KSeF: Frequently asked questions about electronic invoicing in Poland
Is KSeF mandatory in Poland?
Yes, the KSeF system has been mandatory since 1 February 2026 for all companies established in Poland carrying out B2B transactions.
Do foreign companies have to use KSeF?
No, companies not established in Poland are not subject to the obligation, but they may use the system voluntarily.
What is the format of a KSeF invoice?
Invoices must be issued in a structured XML format that complies with the technical requirements of the Polish tax administration.
Can an invoice be sent in PDF format in Poland?
Yes, but only for companies not subject to the KSeF obligation. Companies established in Poland must use the KSeF system.
How long are invoices retained?
Invoices are automatically archived for 10 years in the KSeF system.
Is a KSeF invoice immediately valid upon issuance?
No. An invoice must be submitted to the KSeF system and validated by the tax authorities before it is considered officially issued.
What happens if an invoice is rejected by KSeF?
If rejected, the invoice is not valid. It must be corrected and resubmitted until it is validated by the system.
How do recipients receive an invoice via KSeF?
Invoices are accessible directly through the KSeF system. The recipient is notified and can view or download the invoice from the platform.
Does KSeF apply only to VAT-registered businesses?
Yes, the system applies to B2B transactions between VAT-registered entities established in Poland.
Is KSeF compatible with existing accounting systems?
Yes, but an adaptation is required. Accounting software must be able to generate invoices in a compliant XML format and communicate with the KSeF platform.
Does KSeF operate in real time?
Yes, invoices are transmitted and validated in near real time, enabling better tax control and enhanced traceability.
Are international invoices covered by KSeF?
International transactions may be affected from the perspective of the Polish company, but the requirements depend on the status of the parties and their place of establishment.
Noémie Almot
Community Manager & Copywriter
Noémie is a specialised content writer at ASD Group. She creates and manages blog articles as well as news updates on our websites, with a focus on VAT, international taxes, customs operations, social regulations, and international trade. With her clear and educational writing style, she makes complex and technical topics easily understandable and relevant for businesses.
