KSeF 2026: Poland's e-invoicing mandate explained
KSeF, Poland's National e-Invoicing System, has been mandatory since 2026: from 1 February for businesses with 2024 sales above PLN 200 million and from 1 April for all other VAT payers. Businesses invoicing up to PLN 10,000 a month have until the end of 2026. Every domestic B2B invoice is now a structured FA(3) file cleared by the tax authority.
What KSeF is
KSeF (Krajowy System e-Faktur) is a platform run by the Ministry of Finance and the National Revenue Administration (KAS). A Polish taxpayer submits each B2B invoice to KSeF as an XML file. The system validates it, assigns a unique KSeF number and stores it. An invoice sent online counts as issued on the day it is sent to KSeF and as received when KSeF assigns its number; the buyer retrieves it from the platform. The EU allowed Poland to make this mandatory through Council Implementing Decision (EU) 2022/1003.
This is a clearance model: the tax authority sees the invoice when it is created, not months later in a VAT return. Germany, by contrast, lets invoices travel directly between businesses without a central platform. If you want the background, see the KSeF glossary entry.
Who is covered and from when
📊KSeF timeline (status October 2026)
| Group | Issuing in KSeF | Note |
|---|---|---|
| Sales in 2024 above PLN 200 million incl. VAT | Since 1 February 2026 | Receiving through KSeF also from 1 February 2026 for everyone |
| All other VAT payers | Since 1 April 2026 | Includes small companies and sole traders |
| Any taxpayer invoicing up to PLN 10,000 gross a month | By 1 January 2027 | Exceed the limit and KSeF applies from that invoice on, also in later months |
| Penalties for KSeF errors | From 1 January 2027 | Per the Ministry of Finance FAQ |
| Invoices to consumers | Optional | Not required in KSeF |
All dates come from the official KSeF questions and answers published by the Ministry of Finance. A parliamentary bill (Sejm print 2321) proposed moving the micro-firm deadline to the end of 2027; the official FAQ still shows 31 December 2026, so plan for that date unless the ministry changes it.
Foreign companies without a seat or fixed establishment in Poland are not obliged to use KSeF. A Polish subsidiary of a Berlin or Dublin group, however, is a Polish taxpayer and falls under the mandate like any local firm.
The FA(3) format
Since 1 February 2026 KSeF accepts invoices in the FA(3) logical structure published by the Ministry of Finance. It is a Polish national schema, not the European EN 16931 standard, although both describe similar data. A generic UBL or Peppol file is not accepted; your software must produce FA(3) specifically.
The schema is stricter than a PDF in several places:
- Identifiers. Seller and buyer NIP must be present and valid. A buyer without a NIP, for example a company in Milan, goes into dedicated fields with its EU VAT ID, not into free text. Check foreign VAT IDs with a VAT ID check before you invoice.
- Line detail. Each line carries quantity, unit, net price, VAT rate and amounts. Rounding differences a person would ignore can cause a rejection.
- VAT rates. Poland applies 23 % standard and 8 % and 5 % reduced rates, plus codes for exempt and reverse-charge supplies. Each line needs the right code.
- Corrections. A corrective invoice references the KSeF number of the original, so corrections must come from data that still holds that number.
Authentication and permissions
Before software or an accountant can issue invoices for you, the company has to grant them rights in KSeF. Access works with authorisation tokens, which the ministry has decided to keep without an end date, and with KSeF certificates, usable since 1 February 2026 and valid for up to two years. Both methods run in parallel. The permission model separates issuing, viewing and managing, per entity. If an external accountant in Warsaw invoices for you, settle the rights first, otherwise nothing can be issued.
Buyers outside KSeF
A buyer abroad usually cannot log in to KSeF. The seller therefore delivers the invoice in an agreed way, typically a PDF visualisation, and the visualisation should carry a QR code that lets the buyer verify the invoice in KSeF. For a Polish business that buys from abroad, the reverse applies: foreign suppliers keep invoicing by e-mail, PDF or Peppol, so you run two intake channels at once.
Practical example
A software company in Berlin owns a sales subsidiary in Warsaw. The subsidiary invoices a Polish retailer PLN 12,300 (PLN 10,000 net plus 23 % VAT). Since 1 April 2026 that invoice exists only once KSeF accepts the FA(3) file and returns a KSeF number. The Berlin parent's monthly recharge to the Warsaw entity is a foreign supplier's invoice and stays outside KSeF, but the subsidiary still books it under Polish reverse-charge rules.
The VAT exemption threshold is a separate question
Since 1 January 2026 the Polish VAT registration threshold is PLN 240,000 of annual sales. Being under it does not by itself remove you from KSeF: the micro-firm relief is tied to the monthly value of invoices, not to VAT status. Confirm your position with your accountant rather than assume an exemption.
📋KSeF preparation checklist
- Confirm your group – large taxpayer, standard or micro firm under the PLN 10,000 monthly limit.
- Check your software – FA(3), corrections with KSeF numbers, offline issuing and QR codes on visualisations.
- Set up access – token or KSeF certificate, and rights for your software and accountant.
- Clean master data – NIP numbers, EU VAT IDs, addresses and VAT codes.
- Plan the intake – how invoices from KSeF reach your bookkeeping, and how foreign invoices do.
- Test once end to end – the ministry runs test and demo environments for exactly this.
How Kontevia fits
Kontevia is in early access. Invoices are prepared for KSeF in the FA(3) structure, with room for KSeF numbers and Polish VAT codes, and every incoming invoice is checked against VIES before you pay. The live exchange with KSeF is switched on as early access progresses. See e-invoicing in Kontevia for the current scope.
For a Warsaw small business the advice is simple: if you are not yet issuing in KSeF, you are already late or you rely on the micro-firm relief that ends with 2026. Use the remaining months before penalties apply.
Official sources
- KSeF portal of the Ministry of Finance
- KSeF 2.0 questions and answers
- Council Implementing Decision (EU) 2022/1003 on EUR-Lex
- Polish tax portal podatki.gov.pl
This article is general information and does not replace advice from a tax adviser. Information valid as of 11 October 2026.
Frequently asked questions
- When does KSeF become mandatory for small businesses in Poland?
- Businesses with 2024 sales above PLN 200 million (including VAT) started on 1 February 2026, all other VAT payers on 1 April 2026. Any taxpayer whose invoiced sales total no more than PLN 10,000 gross a month may issue invoices outside KSeF until 31 December 2026.
- Can I still send PDF invoices after KSeF starts?
- A PDF can go to the buyer as a visualisation, but the legally valid B2B invoice is the structured FA(3) document accepted by KSeF. A visualisation for a buyer outside the system should carry the QR code that lets the buyer verify the invoice.
- Does KSeF apply to foreign companies?
- A foreign company without a seat or fixed establishment in Poland is not obliged to issue invoices in KSeF. A Polish subsidiary of a foreign group is a Polish taxpayer and is covered.
- When do KSeF penalties start?
- According to the official KSeF FAQ of the Ministry of Finance, financial penalties for KSeF errors apply from 1 January 2027.
- Do invoices to consumers have to go through KSeF?
- No. Invoices to private individuals who do not run a business do not have to be issued in KSeF, although sellers may use KSeF for them voluntarily.
Topics:KSeFPolande-invoicingFA(3)VATstructured invoice
Kontevia is in early access. Country-specific behaviour described here reflects the rules of each state, not a promise that every feature is live in your country today.
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