The President has signed the act introducing the National e-Invoicing System (KSeF). This means that from 2026, all businesses – both active VAT taxpayers and those exempt from VAT – will be required to issue and receive invoices exclusively through KSeF.
When will KSeF become mandatory?
- February 1, 2026 – for companies with gross sales exceeding PLN 200 million in 2024,
- April 1, 2026 – for all other businesses,
- January 1, 2027 – for micro-entrepreneurs (with monthly sales up to PLN 10,000).
During the transition period (from February until the end of 2026), the law allows certain invoices to be issued outside KSeF – for example, via cash registers – but ultimately, all invoicing will be handled exclusively through the system.
Key changes introduced by the act
- mandatory e-invoicing for all taxpayers – ending the use of paper invoices and PDFs sent by email.
- “offline24” mode – invoices can be issued without internet access (e.g., during system outages) and submitted to KSeF the following business day.
- invoice attachments – businesses will be able to submit certain attachments to e-invoices, provided they register this option in advance via the e-Tax Office.
- shorter VAT refund period – the standard refund period will be reduced from 60 to 40 days.
- no penalties until the end of 2026 – companies will not face sanctions for errors in implementing the new rules during the first year.
- invoice storage in KSeF – invoices will be stored in the system for 10 years.
Challenges and concerns for businesses
Experts highlight that implementing KSeF will be a major challenge, affecting not only accounting departments but also purchasing, sales, IT, and administration teams. Unresolved issues include:
- the right to deduct VAT from invoices issued outside KSeF (e.g., by suppliers not yet prepared for the change),
- determining the correct invoice issue date in offline mode,
- handling employee invoices and invoices issued by foreign contractors.
The KSeF testing environment is expected to be available only in autumn 2025, leaving little time for system integration, testing, and employee training before the February 2026 deadline.
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