---
title: "Mandatory KSeF – New E-Invoicing Rules in Poland from 2026"
type: "page"
url: "https://cnkp.pl/en/blog-en/alerty-2/mandatory-ksef-new-e-invoicing-rules-in-poland-from-2026"
---

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* Mandatory KSeF – New E-Invoicing Rules in Poland from 2026

# Mandatory KSeF – New E-Invoicing Rules in Poland from 2026

[Marcin Kowalski](https://cnkp.pl/en/blog-en/author/marcin-kowalski) [Tomasz Mróz](https://cnkp.pl/en/blog-en/author/tomasz-mroz) 3 September 2025 [Alerts](https://cnkp.pl/en/blog-en/alerty-2)

On **27 August 2025** , the President of Poland signed an amendment to the **VAT Act** , updating the deadlines related to the implementation of **the National e-Invoicing System (KSeF)** .

## **What is KSeF?**

**KSeF** is an IT platform for issuing, accessing, receiving, and storing structured invoices. Its purpose is to centralize the invoicing process in **real time** . The system also enables role and permission management, improving data security and ensuring that invoices are issued only by authorized persons.

The mandatory use of KSeF will apply to most **VAT taxpayers** , both active and exempt.

There are certain **exceptions** . The obligation will not apply to entities that do **not have a registered office in Poland** or that supply goods and services to **individuals not engaged in business activity.**

Furthermore, **VAT RR invoices** documenting the purchase of agricultural products from flat-rate farmers will not fall under the mandatory scheme. Issuing these documents in KSeF will be possible from **1 April 2026** on a voluntary basis. At the same time, from **1 February 2026** , the preferential **40-day VAT refund** period for entities using VAT RR invoices will be abolished.

## **KSeF Implementation Timeline**

KSeF will be rolled out in **two main stages** , with an additional deferral for micro-enterprises:

* **Starting 1 February 2026** – Large taxpayers (sales in 2024 exceeding **200 million** **PLN** including VAT);
* **Beginning 1 April 2026** – All other businesses, except **micro-enterprises** ;
* **Effective 1 January 2027** – **Micro-enterprises** and **businesses with limited digital access** (transactions up to **450 PLN** per invoice and **10,000 PLN** monthly).

## **Transitional Arrangements**

Under the VAT Act amendment of **5 August 2025** , companies with 2024 sales including VAT not exceeding **200 million PLN** may, between **1 February and 31 March 2026** , issue invoices electronically or in paper form.
Companies with monthly sales including VAT not exceeding **10,000 PLN** may, between **1 April and 31 December 2026** , also issue invoices electronically or in paper form.

**Until the end of 2026:**

* invoices from **cash registers** can still be issued;
* **no penalties** will apply for invoicing errors via KseF;
* there is **no obligation** to include the **KSeF number** in invoice payments (including under the **split payment mechanism** ).

Errors or delays in submitting invoices during the first year of mandatory use will **not be sanctioned.**

## **Testing Phase and Pilot Environment**

From **30 September 2025** , the **KSeF 2.0 API** will be open for testing by integrators and large companies.
From **November 2025** , the Ministry of Finance plans to release a test version of the **KSeF Taxpayer Application 2.0,** allowing all businesses to explore the system's functionalities. Invoices issued in the **test environment** will have **no legal effect** , but they offer a unique opportunity to get familiar with KSeF.
The final version of KSeF, enabling invoices to be issued in **real business transactions** , will be available from **1 February 2026** . From that date, taxpayers covered by the schedule will be **required** to issue invoices through KSeF.

## **Certificates**

A **KSeF certificate** will be one of the methods of authentication in the system. From **1 November 2025** , companies will be able to apply for invoice issuer certificates.
The certificate will be required to:

* authenticate invoices **transmitted outside the KSeF system** ;
* confirm the **identity of the issuer** ;
* enable secure login to KSeF and verification of **user permissions.**

Certificates will be issued for **two years** and can be renewed for another **two years** .

**Applications may be submitted by:**

* natural persons listed in the **ZAW-FA notification** ;
* natural persons with **ownership rights** ;
* **legal entities** with ownership rights, using a **qualified electronic seal** (in the case of companies – an **authorized representative** ).

To log into KSeF, one of the following will be required: **a qualified electronic** **signature** , a **qualified electronic seal** , the **Trusted Profile** (Profil Zaufany), or a **KSeF certificate** .

## **Online and Offline Modes, Maintenance and Failures**

KSeF allows invoicing in **two modes** :
**Online mode** – invoices are issued and transmitted in **real time** to KSeF;
**Offline mode** – invoices are initially created outside KSeF and subsequently uploaded to the system, particularly during **maintenance periods, system failures** , or **connectivity issues** .

## **Submission Deadlines**

Deadlines for submitting invoices depend on the reason:
● **System failure** – invoices must be submitted within **7 business days** after the failure ends;
● **Maintenance work** – invoices must be submitted within **1 business day** after availability is restored;
● **Total outage** (e.g. war or natural disaster) – invoices may be issued in **paper form** ;
● **If the issue is on the taxpayer's side** (e.g. internet outage or IT failure), invoices may be issued outside KSeF but must comply with the **FA(3) schema** and be submitted no later than the **next business day** .

## **KSeF Mobile App**

Businesses will also be able to manage invoices via the free **KSeF Mobile App** (version 2.0). The app will be regularly updated and available in the **Google Play Store** and the **Apple App Store** . It will enable management of **vendor profiles** , **customer databases** , and **banking information** .

## **Summary**

The mandatory use of KSeF will be a **significant challenge** for taxpayers. Updates to the **FA(3) invoice schema** and **KSeF 2.0 API** documentation are expected in the coming months.

**Recommended Preparation Steps**
Businesses should verify now whether their **accounting and ERP systems** can handle the updated **FA(3) structure** and are compatible with **KSeF 2.0** . This is the right time to **train your teams** and explore the **pilot environment** .
Even before the go-live date, you can obtain the necessary **certificates** and adapt your **IT infrastructure** – ensuring compliance with confidence and security.

**Critical Timing Considerations**
Since KSeF will become mandatory within **a few months** , we strongly recommend **early preparation** . KSeF implementation coincides with **peak tax season** , when finance and tax teams are already occupied with **tax returns** and **financial reporting (February 1 and April 1, 2026).**

**Important Notice**

This material does **not constitute tax advice** and reflects the legal status as of the date of preparation.

If you have any questions, please do not hesitate to contact us.

*This article has been translated from Polish using an online machine translation system. The translation may contain minor linguistic, stylistic, or interpretative inaccuracies. In case of doubt, we recommend referring to the original version of the text.*

### [Marcin Kowalski](https://cnkp.pl/en/blog-en/author/marcin-kowalski)

Doradca podatkowy, prawnik, absolwent Uniwersytetu im. Adama Mickiewicza w Poznaniu oraz Europejskiego Uniwersytetu „Viadrina” we Frankfurcie nad Odrą, gdzie uzyskał tytuł Master of German and Polish Law (LL.M.) oraz tytuł potwierdzający ukończenie studiów prawniczych w Niemczech – Magister Legum (LL.M.).

##### [Szczegóły BIO](https://cnkp.pl/zespol/marcin-kowalski)

### [Tomasz Mróz](https://cnkp.pl/en/blog-en/author/tomasz-mroz)

Ukończył Wyższą Szkołę Bankową w Poznaniu (obecnie Uniwersytet Merito) na kierunku Zarządzanie oraz studia podyplomowe na kierunku „Gospodarka, rachunkowość i sprawozdawczość budżetowa” na Uniwersytecie Ekonomicznym w Poznaniu. W roku 2024 uzyskał uprawnienia doradcy podatkowego nr 14999.

[Szczegóły w BIO](https://www.cnkp.pl/zespol/tomasz-mroz)

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