Invoicing in Poland, KSeF and the UPO, the ryczałt and the JPK files — written out step by step.
Split payment (MPP) in Poland becomes compulsory for B2B invoices exceeding PLN 15,000 gross that document goods or services listed in Annex 15 to the VAT Act. Omitting the required annotation exposes the seller to an additional tax liability of 30% of the VAT on those sensitive items. The buyer faces the same 30% penalty and loss of tax-deductible costs if they pay via ordinary transfer.
Foreign currency conversion on a Polish VAT invoice requires using the average NBP rate from the last business day preceding the tax point or issue date. For VAT purposes you use the average NBP rate, normally from table A. The KSeF transmission date does not alter this anchor if the invoice is treated under offline24 rules.
A collective correcting invoice in KSeF must carry the details of every corrected original invoice inside the structured XML file. The FA(3) schema does not support loose spreadsheet attachments. Read how to handle bulk volume rebates and populate the required elements correctly. Biurko accepts such corrections from KSeF and links them to the original invoices, but does not issue them.
The repeal of Article 106k on 1 February 2026 ended the use of corrective notes by buyers. Sellers must now correct a wrong buyer NIP by issuing a zero correction invoice followed by a new original invoice.
A rejected invoice never receives a KSeF number, meaning it was never legally issued and cannot be corrected. You must fix the XML file and resend it under the same invoice number. Learn the technical reasons behind validation failures and how to resolve them.
Once an invoice receives a KSeF number, it cannot be cancelled or edited. Since 1 February 2026, all formal and value errors must be corrected solely by the seller. Discover how to handle client disputes, choose the correct schema FA(3) settings, and settle in-minus VAT without waiting for confirmation.
Under the mandatory KSeF system, Polish accounting offices retrieve structured invoices directly from the state repository. Taxpayers must still provide documents that remain outside the system, such as foreign invoices, receipts, and simplified bills. Managing access permissions once and tracking the KSeF number assignment date are now the core requirements for smooth cooperation.
The KSeF platform does not send notifications when a supplier issues an invoice, meaning businesses must actively retrieve them. Additionally, because some micro-businesses can issue paper or PDF invoices until 31 December 2026, a complete purchase register requires combining KSeF imports with manual entries.
ФОП (FOP, Ukrainian sole trader) is not the same as JDG, Дія (Diia) will not open a Polish government portal for you, and KSeF is not ЄРПН. Here is a map of the terms that matter, plus what mandatory e-invoicing changes.
On 1 February 2026 the FA(3) schema replaced FA(2) and the production 1.0 API stopped working. This was a new integration contract, not an upgrade. Main API changes: JWT authentication decoupled from sessions, mandatory encryption of every invoice, KSeF certificates, per-invoice batch processing, new duplicate detection, new permission model. Main schema changes: an attachment node, a new "Employee" party role, the 0% rate and the NP code split into specific codes, flexible payment terms, IBAN up to 34 characters. The consequences are commercial, not only technical: invoice numbering, VAT rate mapping, and who in your accounting team can actually see a client's invoices.
issuing your first invoice in KSeF (Poland's National e-Invoicing System) comes down to three things: authenticating, filling in data that matches the FA(3) structure, and submitting. The system then assigns a KSeF number and returns a UPO (official receipt confirmation). Everything else is detail you can learn in a coffee break.
Handing invoicing to your accountant shouldn't mean handing over passwords, banking details or company settings. This article shows how to give your accountant access in Biurko by email, grant exactly the permissions they need, track every action in an audit log, and revoke access in one click. At the end: how a single accounting office runs all its clients from one login.
When you can't send an invoice to KSeF (Poland's national e-invoicing system) — because your internet dropped, your software is lagging, or you simply can't log in — you don't have to stop selling. offline24 mode lets you issue the invoice outside the system and upload it by the next business day. Below we explain the difference between the four special modes (offline24, offline, emergency, and total outage), walk through offline24 step by step, list the common traps, and show what good software handles for you. No panic, no legal jargon.
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