The Polish Ministry of Finance has published detailed guidance on the implementation of Phase II of the Krajowy System e-Faktur (KSeF) mandatory e-invoicing system, effective from 1 April 2026 for most taxpayers.
Implementation Timeline
The mandatory KSeF system is being introduced in phases: from 1 February 2026 for businesses with sales exceeding PLN 200 million in 2024, from 1 April 2026 for remaining businesses and entities issuing invoices, and from 1 January 2027 for small businesses with monthly invoice sales below PLN 10,000 gross. Small businesses exceeding the PLN 10,000 monthly threshold must begin using KSeF from the invoice that breaches this limit.
System Access and Authentication
Users can access KSeF through ksef.podatki.gov.pl using login.gov.pl credentials (including mObywatel app, e-banking, e-ID or Trusted Profile) or qualified electronic signatures. Non-individual entities without qualified seals must submit form ZAW-FA to designate authorized users. The system uses context-based login where users select which entity they represent when accessing multiple business accounts.
Offline and Emergency Operations
KSeF provides multiple offline modes: offline24 allows invoice issuance without connection but requires submission by the next business day; offline mode applies during system unavailability with submission required within one day of restoration; emergency mode operates during declared KSeF failures with 7 business days for submission after failure ends; and total failure mode for extraordinary circumstances allows invoicing outside KSeF without structural requirements.
Compliance and Penalties
The year 2026 serves as a transitional period with no penalties imposed for KSeF-related errors. The authorities are focusing on practical support through training sessions, sector-specific workshops, and educational materials rather than enforcement.
Context
This guidance represents Poland's comprehensive approach to implementing mandatory B2B e-invoicing, joining other EU member states in digitalizing VAT compliance systems. The phased introduction and penalty moratorium reflect recognition of the significant operational changes required for businesses adapting to structured electronic invoicing requirements.
