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Invoices in KSeF

KSeF? We will take care of your invoices.

KSeF, the national e-invoicing system, is the state system through which invoices between businesses have passed since 2026: instead of emailing an invoice, you issue it in KSeF, and your trading partner sees it straight away. As part of our accounting service we fetch your invoices from KSeF for posting and help you set up permissions. You can stay with your current invoicing software. We work on FinnAI — in the client panel you have your documents, an overview of your accounts and your invoices from KSeF. We have been invoicing in KSeF ourselves since 1 February 2026, before the obligation applied to us.

Timetable

Does this apply to you? When KSeF becomes mandatory.

From
Who it applies to
Criterion
Status
1 February 2026
Largest companies
Sales in 2024 (including VAT) above PLN 200 million
mandatory
1 April 2026
All other companies
All other taxpayers (including those exempt from VAT)
mandatory
1 January 2027
Smallest companies
Sales documented by invoices of up to PLN 10,000 gross a month
mandatory
until 31 December 2026
Cash registers
Invoices from a cash register and receipts showing a NIP (tax identification number) of up to PLN 450 may stay outside KSeF
transitional
—
B2C transactions
Consumer transactions (unless a NIP is given)
voluntary
What it is

The National e-Invoice System in brief.

The National e-Invoice System (KSeF) is a central platform of the Ministry of Finance which, since 1 February 2026, has handled the issuing, receiving and storing of structured invoices in Poland. It covers VAT invoices, corrective invoices, advance invoices and advance-final invoices in B2B trade with other VAT taxpayers — paper and PDF invoices ceased to be permitted in that relationship (apart from the transitional exceptions in the timetable above).

You issue an invoice in your invoicing software or directly in KSeF. It has an XML structure compliant with the FA(3) schema and goes to the Ministry of Finance system; in KSeF the session is authenticated, and the invoice itself is not signed. An invoice is deemed issued on the day it is sent to KSeF, and received by the buyer on the day it is given its KSeF number (Art. 106na(1) and (3)). KSeF gives the invoice an identifying number (the KSeF number). It does not replace the invoice number given by the issuer — the invoice has both. The KSeF number is quoted, among other places, in a corrective invoice, and from 2027 also in bank transfers paying for invoices. The other party collects the invoice directly from KSeF. Archiving is the system's responsibility, for 10 years.

  • A centralised Ministry of Finance platform
  • Invoices in an XML structure (FA(3))
  • Issue date = date of sending to KSeF
  • KSeF number alongside the invoice number
  • 10-year archiving on the Ministry of Finance side
Who it is for

Who KSeF covers.

All active VAT taxpayers

Whatever the legal form — capital companies, partnerships, sole traders and non-governmental organisations that make taxable sales.

Foreign entities and their Polish branches

Foreign entities registered for VAT in Poland that have no fixed place of business here (or whose fixed place of business does not take part in the sales) have no KSeF obligation (Art. 106ga(2)(1)–(2)) — they may use it voluntarily. Polish subsidiaries and branches that take part in sales — on the general rules.

The smallest businesses (until the end of 2026)

Taxpayers — including those exempt from VAT — whose sales documented by invoices do not exceed PLN 10,000 gross a month may issue invoices outside KSeF until 31 December 2026. Anyone who exceeds the threshold in a given month issues invoices in KSeF from the invoice that took them over it.

How we work

How we take over invoicing in KSeF.

  1. 01

    Permissions and access

    at the start

    We help you set up KSeF permissions for the firm and for people in your company — from powers of attorney to tokens.

  2. 02

    Invoices from KSeF

    daily

    As part of our bookkeeping service we fetch your invoices from KSeF for posting. You run the sales; we look after the documents.

  3. 03

    Day-to-day support

    ongoing

    Corrections, offline mode during system outages, changes on the Ministry of Finance side — we follow them and respond on your behalf.

FAQ

Frequently asked questions.

When does KSeF become mandatory?
From 1 February 2026 KSeF applies to taxpayers whose sales in 2024 (including VAT) exceeded PLN 200 million. From 1 April 2026 — to all the others, including those exempt from VAT. Until 31 December 2026 the following may still issue invoices outside KSeF: businesses whose sales documented by invoices do not exceed PLN 10,000 gross a month, as well as invoices from cash registers and receipts showing a NIP of up to PLN 450. From 1 January 2027 — everyone. Source: ksef.podatki.gov.pl.
Can I still issue paper invoices?
Not in B2B relations with VAT taxpayers in Poland — those must go to KSeF. Outside the system remain B2C invoices for consumers (unless the buyer gives a NIP), OSS/IOSS invoices, fiscal receipts and invoices issued outside Poland. Until 31 December 2026 invoices from cash registers and receipts showing a NIP of up to PLN 450 (simplified invoices) may still be issued outside KSeF, as well as invoices of businesses whose invoiced sales do not exceed PLN 10,000 gross a month. From 2027 — everything in KSeF.
What happens if KSeF is unavailable?
The law provides for several modes. An invoice can always be issued ‘offline’ and sent to KSeF by the next working day at the latest. If the system is unavailable and the Ministry of Finance has announced it — by the next working day after the unavailability ends. In the event of a failure announced by a Ministry of Finance notice — within 7 working days of the day the failure ends. A trading partner who receives an invoice outside KSeF is given it with QR codes. We keep track of these deadlines for you.
What about foreign-currency invoices and intra-EU supplies and acquisitions of goods (WDT/WNT)?
Foreign-currency invoices are issued in KSeF with the amount in the foreign currency and the tax converted into PLN at the average rate of the National Bank of Poland (NBP) from the last working day before the tax obligation arises (or, where the invoice is issued earlier, before the day it is issued). You issue a WDT invoice in KSeF; the foreign buyer receives it outside the system, with a QR code. A WNT is documented by the foreign supplier's invoice — it does not go to KSeF, and we book it from the supplier's document. VAT RR invoices for flat-rate farmers can be issued in KSeF from 1 April 2026.
Do you offer support in English?
Yes. We keep the books and talk to clients in English as well.

Let's talk about KSeF for your business.

Write to us — we will tell you plainly how invoicing in KSeF works as part of our accounting service and what to prepare at the start.

Get in touch