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KSeF 2026 for sole traders — what you need to know
Running a sole proprietorship and issuing invoices? Here is when KSeF applies to you and the simplest way to issue invoices — including for free.
Where things stand
Since 1 April 2026 most businesses issue their invoices in KSeF. If your invoiced sales do not exceed PLN 10,000 gross a month, you may issue invoices outside KSeF until 31 December 2026. From 1 January 2027 KSeF applies to everyone.
What KSeF is
KSeF (Krajowy System e-Faktur, the National e-Invoicing System) is the Ministry of Finance system in which invoices are issued and received. An invoice in KSeF is an FA(3) XML file — a structured document, not a PDF sent by email.
In practice you issue an invoice in software that supports KSeF, or in the free KSeF 2.0 Taxpayer Application (Aplikacja Podatnika KSeF 2.0). Since 1 February 2026 you have received your suppliers' invoices through KSeF.
Your options
- The free KSeF 2.0 Taxpayer Application or the KSeF 2.0 mobile app — enough if you issue a few invoices a month.
- An invoicing program — convenient if you invoice regularly; KSeF is usually included in the subscription.
- An accounting office — if the office issues invoices on your behalf, you have to grant it permissions in KSeF.
The Ministry of Finance describes the detailed rules, including those for VAT-exempt businesses (in Polish), at ksef.podatki.gov.pl. If in doubt, ask your accountant.
Frequently asked questions
Does KSeF apply to sole traders (JDG)?
Yes. Since 1 April 2026 KSeF has applied to most businesses, including sole proprietorships. Businesses whose invoiced sales do not exceed PLN 10,000 gross a month may issue invoices outside KSeF until 31 December 2026. From 1 January 2027 KSeF applies to everyone.
What if I go over the PLN 10,000 limit in a given month?
From the invoice that takes you over the limit, you must issue invoices in KSeF — in the following months too, even if your sales drop back below the limit.
How much does KSeF cost?
Access to KSeF is free. The Ministry of Finance also provides the free KSeF 2.0 Taxpayer Application and the KSeF 2.0 mobile app. Paid invoicing software is more convenient if you invoice often, but it isn't required.
Do I need to know XML?
No. In the Ministry's application and in invoicing programs you fill in a form — the program prepares the XML in the FA(3) format.
What happens if I don't use KSeF?
Under current law, penalties apply from 1 January 2027 and can reach 100% of the VAT on the invoice. The government has adopted a bill that extends the penalty deferral to 31 December 2027 (status as of October 2026). The obligation to use KSeF itself applies regardless of penalties.
This English version is a translation of the Polish original, provided for convenience. It describes Polish law, and the Polish version prevails. It is for information only and is not tax advice.