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Poland's National e-Invoice System (e-invoicing)
KSeF (Krajowy System e-Faktur) is Poland's centralized government electronic invoicing platform, administered by the Ministry of Finance. It has been mandatory for large companies since February 2026 and for most VAT taxpayers in Poland since April 2026. Full coverage, including micro-businesses, follows from January 2027. According to Terminovo platform data, most small businesses complete their KSeF setup in under a day.
Last updated: August 19, 2026
Three dates you need to know, regardless of company size:
| Date | Who it affects | What changes |
|---|---|---|
| February 1, 2026 | Large companies (turnover above 200M PLN) | Mandatory to issue invoices via KSeF. Every business โ regardless of size โ must already be able to receive them. |
| April 1, 2026 | Small and medium businesses (SMEs) | Mandatory to issue invoices via KSeF for businesses with monthly sales above 10,000 PLN. |
| January 1, 2027 | Micro-businesses | Mandatory to issue invoices via KSeF. Financial penalties begin โ up to 100% of the VAT amount on the invoice. |
Krajowy System e-Faktur
Polish Ministry of Finance
~2.5M VAT taxpayers
XML (FA(2) schema)
10 years by government
~10 seconds
KSeF (Krajowy System e-Faktur, or National e-Invoice System) is Poland's government platform for issuing, transmitting, and storing structured electronic invoices in XML format. Learn more in our complete KSeF 2026 guide.
The system acts as a central hub through which all B2B invoices in Poland pass. Each invoice receives a unique KSeF number and is stored by the state for 10 years. The official portal is ksef.podatki.gov.pl, and the Ministry of Finance publishes the formal requirements at podatki.gov.pl.
The system assigns this number not when you send the invoice, but only once it passes validation. The distinction matters in practice: until the number comes back, the invoice formally does not exist in KSeF, even if it was transmitted correctly.
The number is 35 characters long: 32 characters of data plus 3 hyphens separating the segments: NIP-YYYYMMDD-XXXXXXXXXXXX-XX
The KSeF number appears on the invoice once it has been accepted โ in the KSeF portal, in the PDF visualization generated by the system, and in the official confirmation of receipt (UPO). If you use invoicing software, the number is added automatically to the document your customer sees.
Your invoice number (e.g. FV/08/2026/001) is your own numbering, assigned at the moment you issue the document โ it keeps your books in order and must run sequentially within an accounting period. The KSeF number is assigned by the system, only after acceptance, and is used to verify authenticity and delivery. Both numbers appear on the same invoice but serve different purposes.
February 1, 2026
ActiveLarge Companies + Receiving
Companies with turnover >200M PLN must ISSUE via KSeF. ALL businesses must be ready to RECEIVE invoices.
April 1, 2026
ActiveSmall & Medium Businesses
Mandatory KSeF issuing for businesses with monthly sales >10,000 PLN.
January 1, 2027
Micro-businesses + Penalties
Mandatory for micro-businesses (โค10k PLN/month). Financial penalties of up to 100% VAT begin.
After several months of mandatory KSeF, it is clear which problems are real and which turned out to be harmless. Issuing invoices is rarely the difficulty in itself โ accounting software caught up with the integration. The trouble shows up elsewhere.
The obligation to receive invoices from KSeF has applied to every business since February 2026, yet many companies prepared only for issuing them. According to research by the Union of Entrepreneurs and Employers (ZPP, 2026), before the February deadline 87% of businesses were unaware of the obligation to receive invoices via KSeF โ which explains why some are still catching up on the basics after the system went live, instead of handling them earlier.
When KSeF is unavailable โ because of an outage on the system side or a lost connection on yours โ offline24 mode applies: you issue the invoice according to the XML schema and have until the end of the next business day to send it to the system. In practice the most common failure is not the mechanism itself but the missing procedure โ a team that does not know who has to do it, or by when.
Alongside the Trusted Profile (Profil Zaufany) and the qualified electronic signature, KSeF 2.0 extends authentication with KSeF certificates โ intended mainly for accounting systems, tax agents and API integrations that run without a person logging in. Companies using ready-made software (such as Terminovo) usually do not have to deal with this themselves; the integration provider does it.
Inspections focus on three areas: whether the data matches the FA(2) schema, whether contractor NIP numbers are correct (a wrong NIP means the invoice is accepted by KSeF but the recipient never sees it), and whether invoices issued offline were submitted on time. None of this carries a financial penalty until the end of 2026 โ but irregularities can still lead to a dispute over VAT deduction.
Issue KSeF-compliant invoices from Poland and automate payment reminders in one tool. Free to start.
Create free account| Feature | Traditional | KSeF |
|---|---|---|
| Invoice Format | PDF, paper | XML (structured) |
| Delivery | Email, postal | Automatic via API |
| Proof of Delivery | None or confirmation | Official UPO |
| Archiving | Self-managed (10 years) | Government (10 years) |
| Authenticity Check | Difficult | Instant |
| VAT Refund | 60 days | 40 days |
| Legal Status | Document | Official document |
40 days instead of 60 - get your money from the tax office 33% faster.
KSeF invoices have official document status. Debtors cannot claim they didn't receive the invoice.
No need to store invoices - KSeF does it for 10 years. No more filing cabinets.
Purchase invoices automatically flow into your system. No more manual data entry.
A Trusted Profile (free at login.gov.pl) or a qualified electronic signature is required to use KSeF. Without one, you cannot issue e-invoices.
Your invoicing software must support the FA(2) format and KSeF API communication. Terminovo offers this integration for free โ even on the free plan.
The Ministry of Finance provides a KSeF test (pre-production) environment. Issue a few test invoices, check KSeF numbers, and verify that your data is correct.
Finance, sales, and customer service must understand what a KSeF invoice number is, how the issuing process works, and what changes in document archiving.
After successful testing, switch to the production environment. From that point on, every invoice you issue goes directly into the National e-Invoice System.
The obligation covers every active VAT taxpayer issuing B2B invoices in Poland, regardless of legal form. Sole proprietorship, limited liability company, joint-stock company, general partnership: what counts is VAT status and turnover, not the form of the business. The deadline depends on size: large companies from February 2026, all other active VAT taxpayers from April 2026, and micro-businesses from January 2027 (see the full deadline table above).
The obligation does not apply to every entity or every transaction. The most common exclusions:
Micro-entrepreneurs with sales up to 10,000 PLN per month have until January 2027 to start issuing invoices via KSeF. That exemption covers issuing only โ the obligation to receive supplier invoices through KSeF has applied to them, like every other business, since February 2026.
Running a sole proprietorship (JDG) or a small business? KSeF applies to you exactly like it applies to large companies โ only the deadline differs. If you are an active VAT payer, the obligation to issue invoices via KSeF applies to you from April 1, 2026, unless your monthly sales are below 10,000 PLN โ in which case you have until January 1, 2027. One catch: the obligation to RECEIVE invoices from suppliers via KSeF applies to every business from February 1, 2026, regardless of size. This is the most common trap: businesses prepare to issue invoices but forget they need to be able to receive them even earlier.
In practice, there are three things to do. First, get a Trusted Profile (Profil Zaufany) โ it is free, via login.gov.pl. Second, choose invoicing software with KSeF 2.0 integration. Third, issue a few test invoices before your deadline arrives. You do not need an accounting team or an IT department โ a well-built tool walks you through the whole process step by step. Invoicing through KSeF is not harder than issuing a regular invoice โ the difference is that the invoice goes to the Ministry of Finance system first, then to your client. With Terminovo, KSeF invoicing is free on every plan, so you can get started today without deadline pressure.
KSeF does not replace JPK_VAT โ the two obligations run in parallel and cover different things. KSeF concerns the act of issuing and exchanging an invoice: the system validates the document, assigns it a number and stores it. JPK_VAT (the JPK_V7 structure) is the monthly settlement with the tax office โ a summary of transactions for tax purposes that you still have to prepare and file separately.
In practice this means that invoice data in KSeF does not automatically flow into your JPK file, unless your accounting software automates it. KSeF also does not release you from other obligations: CIT or PIT returns, social security (ZUS) contributions, or future structures such as JPK-CIT. In short: KSeF puts invoicing in order, but it does not replace tax reporting as a whole.
From January 1, 2027, the Ministry of Finance imposes penalties for not issuing invoices via KSeF. Until the end of 2026 there is a transition period with no financial sanctions.
Penalties are calculated per invoice issued outside KSeF โ they can accumulate rapidly at high invoice volumes.
| Violation | Penalty |
|---|---|
| Failure to issue an invoice via KSeF | Up to 100% of VAT on the invoice |
| Invoice issued not conforming to the FA(2) schema | Up to 100% of the VAT amount on the invoice |
| Missing KSeF number assignment | Invoice treated as not issued โ penalties the same as for a missing invoice |
The amount depends on whether the invoice shows VAT. The head of the tax office may impose a penalty of up to 100% of the VAT shown on an invoice issued outside KSeF. If the invoice shows no VAT โ for example for VAT-exempt taxpayers โ the penalty is up to 18.7% of the total amount due on that invoice. Both rates are ceilings, not automatic amounts: the tax office takes the circumstances into account, including whether the breach was a one-off or systematic.
The transition period runs until the end of 2026 โ time to test your processes, not to postpone them. Three things are worth doing in advance: check in the KSeF test environment that your invoices pass FA(2) validation without errors; verify the NIP numbers in your contractor database โ a wrong NIP means the invoice reaches the system but the recipient never sees it; and write down a simple outage procedure (offline24) so your team knows what to do when KSeF is unavailable. Companies that do this before January 2027 avoid both the penalties and the scramble in the final week before the deadline.
Yes. From February 1, 2026, all businesses must receive invoices via KSeF. From April 1, 2026, most must also issue. Only micro-businesses (โค10k PLN/month) can wait until January 2027.
No penalties until end of 2026. From January 2027, penalties can reach 100% of the VAT amount. Also, invoices issued outside KSeF may be challenged.
Yes. In offline24 mode you can issue invoices without KSeF connection. You must submit them to the system by the next business day.
KSeF access itself is free. The cost is integration software - from 0 PLN (Taxpayer App) to 30-200 PLN/month for professional solutions like Terminovo.
After mandatory KSeF is implemented, paper and PDF invoices will not be recognized as valid VAT invoices for B2B transactions between VAT taxpayers in Poland. A paper invoice issued instead of a KSeF e-invoice will be treated as a document that does not meet statutory requirements. Exceptions apply to B2C transactions and the specific cases listed in the exemption regulations.
KSeF dramatically simplifies archiving. Invoices issued and received through KSeF are stored by the Ministry of Finance for 10 years, relieving companies of the obligation to archive these documents themselves. You still need to store invoices outside the system (e.g. B2C, foreign) on your own. Access to archived invoices is available via the KSeF API or the KSeF portal.
Generally no โ invoices issued to foreign entities without a registered office or permanent establishment in Poland are excluded from the KSeF obligation. You may, however, voluntarily issue such invoices through KSeF. Export invoices, intra-EU supply invoices, and services rendered to foreign contractors remain outside the scope of the obligation, though it is always advisable to verify with a tax advisor.
Every KSeF invoice receives a unique KSeF number and a QR code. Verification can be done via the e-Tax Office website, the KSeF API, or the Ministry of Finance app. Simply enter the KSeF number or scan the QR code to confirm the invoice is authentic and has not been modified after issuance. This eliminates the risk of fraudulent invoices in B2B transactions.
KSeF (Krajowy System e-Faktur โ the National e-Invoice System) is Poland's mandatory, government-run platform for structured B2B e-invoicing, operated by the Ministry of Finance. Every B2B invoice between VAT taxpayers in Poland must be issued through KSeF in XML format, validated, assigned a unique number, and stored centrally. It applies to foreign companies that have a fixed establishment in Poland for VAT purposes.
A KSeF number is the unique identifier the system assigns to every invoice once it is accepted. It confirms the invoice is registered in the national system, fixes the official issue date, and lets both parties retrieve the same canonical version. The number (and its QR code) is how an invoice is verified โ there is no valid KSeF e-invoice without one.
Per the Polish Ministry of Finance: from 1 February 2026 large companies (turnover above 200M PLN) must issue invoices via KSeF and all businesses must be able to receive them; from 1 April 2026 the obligation extends to small and medium businesses (sales above 10,000 PLN/month); micro-businesses join from 1 January 2027, when financial penalties also begin to apply.
Yes. A sole proprietorship (JDG) follows the same rules as any other business โ what matters is turnover, not legal form. If you are an active VAT payer, you must issue invoices via KSeF from April 1, 2026 (or from January 1, 2027 if your monthly sales are below 10,000 PLN). The obligation to receive invoices from suppliers already applies from February 1, 2026.
KSeF itself is free โ the Ministry of Finance does not charge for it. Costs can come from the invoicing software you use: some programs charge a subscription. KSeF invoicing in Terminovo is free on every plan, with no document limits and no hidden fees.
No penalties apply until the end of 2026. From January 1, 2027, failing to issue an invoice via KSeF can result in a penalty of up to 100% of the VAT amount on the invoice. An invoice issued outside the system may also be treated as invalid for VAT purposes.
When KSeF is unavailable for technical reasons on the Ministry of Finance side, the same procedure applies as in offline24 mode: you issue the invoice according to the XML schema and send it to the system no later than the next business day after the outage ends. It is worth having a short written procedure for this โ who issues the offline invoice, where it is stored, and who tracks the submission deadline.
There is no such obligation. Invoices issued to private individuals who do not run a business (B2C) stay outside the scope of KSeF โ the consumer does not need an account in the system. You can still issue such an invoice through KSeF voluntarily if your software supports it.
In practice the process looks like this: you issue the invoice in your software as usual, the software converts it into XML matching the FA(2) schema and sends it to KSeF, and after verification โ usually within about 10 seconds โ the system assigns a KSeF number and returns the official confirmation of receipt (UPO). Only from that moment is the invoice officially issued.
Yes, with a corrective invoice โ correction notes (noty korygujฤ ce) are no longer used in KSeF. A correction can increase or decrease the invoice value (in plus / in minus) and does not require the buyer to confirm receipt. If you want to cancel an incorrect document entirely, you issue a correction "to zero" โ the same data, with an amount of 0 PLN.
The KSeF number uniquely identifies one specific invoice in the system, so quoting it in the payment reference lets you match an incoming payment to the right document automatically โ without manually comparing amounts and dates. In Terminovo this solves a classic accounting problem: hundreds of transfers with no clear link to an invoice.
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