KSeF from 1 January 2027: what to do before then

From 1 January 2027 an invoice you issue to another business must, as a rule, go through KSeF (Krajowy System e-Faktur, Poland's national e-invoicing system), whatever the amount. The art. 145m exemption of the VAT Act, the 10,000 PLN monthly limit, applies only until 31 December 2026, and from the new year there is no threshold for anyone, VAT-exempt taxpayers included.

From the same date a cash register can no longer issue invoices, and a receipt with a NIP (tax ID) stops counting as a simplified invoice. Legal position as of 7 October 2026.

VAT Act, Dz.U. 2026 item 1263, art. 145m

What exactly ends on 31 December

Art. 145m(1) allowed paper or electronic invoices outside KSeF between 1 April and 31 December 2026, as long as monthly sales documented by such invoices did not exceed 10,000 PLN gross. How the limit was counted is explained in KSeF's 10,000 PLN limit. After 31 December the provision lapses and the duty in art. 106ga(1) covers every taxpayer. The MF roadmap describes this as the date KSeF becomes mandatory "for everyone".

MF: KSeF 2.0 implementation stages

Several things change in practice:

• VAT-exempt taxpayers. An exempt taxpayer (art. 113) still issues an invoice only on the buyer's request (art. 106b(3)(2)), but when they issue one to another taxpayer, it goes through KSeF. The art. 113 exemption is not an exception to KSeF (the exceptions are listed below). Ewa, a hairdresser exempt from VAT who issues a 400 PLN invoice to a beauty salon every few months, issues it in KSeF from January.
• Cash registers. Art. 145n allowed invoices from a cash register until the end of 2026, and a receipt with a NIP (up to 450 PLN or 100 EUR) counted as a simplified invoice. That ends on 1 January 2027. A business customer who wants an invoice gets it from KSeF.
• Consumers. Invoices to private individuals who do not run a business stay outside the obligation (art. 106ga(2)(4)).
• Bank transfers. A buyer who is an active VAT taxpayer and pays an invoice to another active VAT taxpayer must put the KSeF number in the transfer (art. 108g(1), for payments from 1 January 2027).

KSeF 2.0 Handbook, part I, p. 14

The permanent exceptions are few: art. 106ga(2) of the VAT Act lists, among others, sellers with no seat or permanent establishment in Poland, special procedures and the art. 113a exemption (point 6), and the Ministry of Finance regulation (Dz.U. 2025 item 1740, § 2) lists, among others, invoices for toll motorway travel and single tickets for passenger transport.

MoF regulation on cases with no structured invoice duty, Dz.U. 2025 item 1740, § 2

What counts is the invoice issue date: an online invoice is issued on the day it is sent to KSeF. From the wording of art. 145m it follows that an invoice for a December service issued on 4 January 2027 is already a 2027 invoice and goes through KSeF.

A plan for the last weeks

Order matters: without a login you cannot grant permissions, and without software you cannot test issuing. Our example is Ania, a graphic designer running a JDG (sole proprietorship), who issues 3-4 invoices a month to agencies and has so far stayed under the limit.

1. Choose how you log in

A private individual logs in to KSeF through the national node (login.gov.pl: Profil Zaufany, the mObywatel app, online banking or an e-ID card), with a qualified electronic signature, with a token or with a KSeF certificate. The first method is free, and the login context is your NIP. The duty to receive invoices through KSeF has applied since 1 February 2026 regardless of the limit, and covers invoices issued in KSeF (Handbook part II, p. 96), so if you already check them there, you have this step covered.

Tokens are uncertain. The regulation allows them until 31 December 2026 (§ 13), MF has announced it will keep them, but no amendment has been published. If your software logs in with a token, ask the vendor about its plan. We describe the differences in certificates vs tokens.

KSeF 2.0 Handbook, part I, pp. 21 and 26 KSeF 2.0 Handbook, part II, p. 96

2. Choose software

MF offers the Aplikacja Podatnika KSeF (browser-based, ap.ksef.mf.gov.pl), the KSeF mobile app and e-mikrofirma for free. The handbook states that they can be the long-term tool for issuing invoices from 1 January 2027. For a few invoices a month that is enough. If you use invoicing software, check that the vendor integrates with the KSeF 2.0 API and supports the offline modes. A shop with a cash register needs a tool for issuing invoices outside the register, because from January the register cannot do it.

KSeF 2.0 Handbook, part II, p. 96

3. Grant your accountant permissions

As a private individual you grant permissions electronically in the Aplikacja Podatnika, without a ZAW-FA notification. You pick the scope: viewing invoices (the accounting office downloads and books them) or issuing as well. The handbook describes three models: an office with no KSeF access, an office with access to invoices, and an office that issues invoices on the client's behalf. Agree with your accountant which one you use before you issue the first invoice in January.

Aplikacja Podatnika manual, pp. 136-145

4. Test issuing and receiving

MF has provided a test environment and a pre-production (Demo) environment of the Aplikacja Podatnika, and if you use software, ask the vendor whether it offers testing. Issue a test invoice, see how it looks on the recipient's side, and check what the software shows when KSeF rejects a file. The most common reasons for rejection are in the most common FA(3) validation errors.

5. Decide what you do in an outage

Offline invoices follow the FA(3) template and must be sent to KSeF within a deadline. Issuing offline requires a KSeF certificate, so download one in advance.

In a total failure announced in the mass media, invoices are issued outside KSeF and are not sent afterwards.

KSeF 2.0 Handbook, part I, pp. 23-24

6. Issue the first invoice in January

Send it to KSeF on the day you issue it. An online invoice counts as issued on the day it is sent, and one sent a day later is treated as an offline24 invoice. For a domestic buyer with a NIP you issue nothing beyond sending it to KSeF; they download it from the system after logging in or via a link or QR code, so you do not need to email them a PDF or the KSeF number. For a foreign buyer you issue the invoice in KSeF and also pass it on in an agreed way, as we describe in foreign invoices in KSeF.

KSeF 2.0 Handbook, part II, p. 97