KSeF

KSeF 2.0 – company obligations in 2026: a complete guide

From 1 February 2026 the National e-Invoice System is mandatory for the largest VAT payers, and from 1 April for all the others – including those exempt from VAT. The article explains exactly who is covered, from when penalties apply and what to do if you are not yet ready.

Profais Team

Accounting firm in Łódź · KIBR member

15 April 2026 · updated 22 October 2026 · 9 min read

From 1 February 2026 (the largest taxpayers) and from 1 April 2026 (the others), invoices between Polish VAT payers must go through KSeF (the national e-invoicing system), that is, the central system of the Ministry of Finance (MF). Paper and PDF invoices are no longer permitted in this relationship. The legal basis is the VAT Act (Articles 106ga–106nha) and the MF regulations on the FA(3) structure (the binding template of the invoice file) and the method of sending.

The obligation came into force gradually: on 1 February 2026 it covered the largest taxpayers (2024 sales over PLN 200 million), and on 1 April 2026 all the other taxpayers, including those exempt from VAT. Until 31 December 2026 the smallest taxpayers may still issue invoices outside KSeF (up to PLN 10,000 gross a month, Article 145m of the VAT Act); from 1 January 2027 – everyone. Penalties for issuing an invoice outside KSeF apply only from 1 January 2027, details in the “Penalties” section.

Implementation timetable

The Ministry of Finance adopted a phased timetable. The first cut-off date depends on the value of sales in 2024, the next ones on the amount of sales documented by invoices.

| Date | Segment | Criterion | |------|---------|-----------| | 1 February 2026 | Large taxpayers | 2024 sales over PLN 200 million | | 1 April 2026 | Other taxpayers | All other taxpayers (including those exempt from VAT) | | until 31 December 2026 | Cash registers | Invoices from a cash register and receipts with a NIP (tax identification number) up to PLN 450 may be outside KSeF (transitionally) | | 1 January 2027 | The smallest companies | Sales documented by invoices up to PLN 10,000 gross in a month – until the end of 2026 they may still issue outside KSeF |

Who must implement KSeF

The obligation applies to all taxpayers established in Poland – regardless of legal form (a sole trader business, partnerships, capital companies) and industry, including those exempt from VAT. KSeF covers sales and purchase invoices in dealings between companies (B2B) with other Polish taxpayers, including corrective, advance and final advance invoices. Outside the system remain invoices for consumers (B2C), fiscal receipts, sales under the OSS and IOSS procedures (EU distance sales to consumers), invoices issued outside Poland and – until 31 December 2026 – invoices from cash registers and receipts with a NIP up to PLN 450 (simplified invoices).

VAT payers – all, regardless of industry
The smallest taxpayers (including those exempt from VAT), whose sales documented by invoices do not exceed PLN 10,000 gross a month – may issue outside KSeF until 31 December 2026 (Article 145m of the VAT Act)
Foreign entities registered for VAT in Poland that have no fixed establishment here (or it does not take part in the sales) have no KSeF obligation (Article 106ga(2) points 1–2) – they may use it voluntarily. Polish subsidiaries and branches taking part in the sales – on the general rules
Non-governmental organisations making taxable sales – on the general rules

Exceptions

Outside KSeF remain: (1) invoices for consumers (B2C), unless the buyer gave a NIP, (2) receipts from fiscal cash registers, (3) temporarily, until 31 December 2026 – invoices from cash registers and receipts with a NIP treated as simplified invoices (Article 145n of the VAT Act), (4) OSS and IOSS invoices for e-commerce sales to consumers in other EU countries, (5) invoices issued by foreign branches outside Poland. A separate matter is (6) VAT RR invoices (for flat-rate farmers) – from 1 April 2026 they can be issued in KSeF voluntarily (Article 17c of the Act of 16 June 2023 as worded in 2025).

Penalties for non-compliance

Financial penalties for issuing an invoice outside KSeF or failing to send it on time (Article 106ni of the VAT Act) apply from 1 January 2027. In 2026 the act does not provide for such penalties. Fiscal criminal proceedings are also not initiated for these failings (Article 106ni(4)). Even so, the invoice must reach KSeF, and a document issued contrary to the rules must be corrected.

How to prepare

Even after the date of the obligation, companies that have not yet implemented KSeF can catch up in an organised way. The starting checklist includes:

A review of invoicing processes – where invoices come from, who issues them, in which programs
The invoicing program – check whether your program sends invoices in the FA(3) structure; if not, it must be updated
Granting KSeF permissions – for key employees (accounting, sales)
A pilot – with selected customers before the full launch
Training the teams – accounting and sales
An emergency procedure – offline mode (sending by the next working day at the latest) and the procedure for an outage announced by the MF (7 working days from its end)

Summary

KSeF 2.0 is already a reality for most Polish companies – from 1 April 2026 it applies to all other taxpayers, including those exempt from VAT, and from 1 January 2027 nobody will issue an invoice outside KSeF. The implementation is not only an IT project – it touches sales processes, permissions, handling of complaints and tax reporting. You can stay with your own invoicing program – we help with the implementation and with granting permissions, and as part of our accounting service we fetch your invoices from KSeF for posting. See our KSeF service.

Sources: ksef.podatki.gov.pl, ksef.mf.gov.pl, podatki.gov.pl, the VAT Act Articles 106ga–106nha, Articles 145l–145n.

FAQ

Frequently asked questions

From exactly when do I have to be in KSeF?

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: companies whose sales documented by invoices do not exceed PLN 10,000 gross in a month, and also invoices from cash registers and receipts with a NIP up to PLN 450. From 1 January 2027 – everyone. Source: ksef.podatki.gov.pl.

What if my invoicing program does not support KSeF?

You have three options: (1) update the program to a version that supports KSeF and sends invoices in the FA(3) structure, (2) stay with your program and use our help with the implementation, (3) issue invoices manually in the Ministry of Finance portal (ksef.mf.gov.pl) – this is convenient only with few invoices.

Do invoices from KSeF have a number?

Yes. KSeF assigns 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 given, among other places, in a corrective invoice, and from 2027 also in transfers for invoices.

How long should invoices in KSeF be kept?

The system stores invoices sent to KSeF for 10 years from the end of the year in which they were issued – for VAT purposes you do not have to archive them separately. Other documents (receipts, invoices from outside KSeF, such as foreign ones, contracts, statements) you continue to keep for the periods in the Accounting Act and the Tax Ordinance Act.

What about foreign invoices?

KSeF concerns a Polish issuer. If you issue an invoice for a foreign customer (for example, a WDT, that is, an intra-Community supply of goods), you issue it in KSeF, and the foreign buyer receives it outside the system, with a QR code. If you are the one receiving an invoice from a foreign supplier, that document stays outside KSeF and you book it in the classic way.