Invoice for a private individual: KSeF or PDF?
PDF is fine: invoices to private individuals are outside mandatory KSeF, after 2026 too. You can issue one there voluntarily and send it with a QR code.
Step-by-step guides →
- Issuing and receiving invoices
Receiving invoices in KSeF: nothing to accept
13 min read - Issuing and receiving invoices
Your first real invoice in the KSeF Taxpayer App
8 min read - Issuing and receiving invoices
KSeF outage: what to do and when to send
10 min read - Login and permissions
KSeF login: Profil Zaufany or qualified signature
8 min read - Login and permissions
Giving your accountant KSeF access: step by step
8 min read - Issuing and receiving invoices
KSeF test invoice: try it before you go live
6 min read
Cash register invoices and NIP receipts in 2027
Until 31 Dec 2026, cash-register invoices and NIP receipts up to PLN 450 can stay outside KSeF. From 2027 a business buyer's invoice comes from KSeF.
KSeF penalties: duty in 2027, fines from 2028?
KSeF is mandatory from 1 January 2027 with no limit. The MoF wants to move art. 106ni fines to 2028, but draft UD477 is not yet law.
KSeF from 1 January 2027: what to do before then
From 1 January 2027 the 10,000 PLN limit is gone: invoices to businesses go through KSeF as a rule, VAT-exempt sellers included. A preparation plan.
Strict XML validation in KSeF from 19 Oct 2026
From 19 October 2026 KSeF rejects invoices with XML processing instructions or discouraged Unicode characters. Until then it warns via X-System-Warning.
KSeF number in a bank transfer: from 2027
From 1 January 2027, active VAT payers must put the KSeF number in the transfer title when paying active VAT payers. For several invoices: a collective ID.
KSeF tokens after 2026: what we know
The KSeF regulation allows tokens only until 31 Dec 2026. MF and the API team say they will stay, but the rule is unchanged. What to do now.
VAT-exempt and KSeF: when your invoices go in
VAT exemption does not exempt you from KSeF. Invoices to businesses go through it as a rule; the 10,000 zł limit works until the end of 2026, then it is gone.
Fake invoice in KSeF: what to do
You can't reject a fake invoice in KSeF. Don't pay it, check the NIP on the Biała Lista and report it with the “Zgłoszenie nadużycia” button.
Corrective invoice in KSeF: how to issue one
You can't edit a KSeF invoice. Issue a KOR correction that cites the original's KSeF number and enters the difference: −500 zł, not the new 4,500 zł.
KSeF is live: first steps and the 10k limit
KSeF applies from 1 April 2026. Up to 10,000 PLN a month you can stay outside it until year-end, and the invoice issue date decides.
KSeF checklist: 10 things before invoice one
10 things to check before your first KSeF invoice: FA(3) software, login, tests, offline mode, accountant access. Written for sole traders.
Invoicing a foreign buyer in KSeF
EU buyer: KodUE + NrVatUE, not NIP. Non-EU: KodKraju + NrID. Plus the np I, np II, 0 WDT and 0 EX rates and ready-to-use XML examples.
KSeF token or certificate: how to log in (2026)
Profil Zaufany is enough for manual login. Invoicing software connects to KSeF with a token or a KSeF certificate. What to pick in your situation.
FA(2) vs FA(3): what to change in your XML
Since 1 February 2026 KSeF accepts only FA(3). Change the namespace, KodFormularza and WariantFormularza, add JST and GV to Podmiot2. Corrections too.
KSeF 10,000 PLN limit: how to count it
The limit is counted monthly, on gross amounts, from B2B invoices only. After crossing it there is no return to PDF; from 1 January 2027 KSeF covers everyone.
12 most common FA(3) validation errors
Wrong namespace, element order, NIP, dates, P_12, Adnotacje: the 12 most common FA(3) errors with the cause and a copy-ready XML fix for each.
KSeF for sole traders: what you must do
From 1 April 2026 every taxpayer issues B2B invoices in KSeF, VAT-exempt included. Until the end of 2026 you can stay outside it up to 10,000 PLN a month.
KSeF from 1 April 2026: who must use it
From 1 April 2026 you issue B2B invoices in KSeF, VAT-exempt taxpayers included. Until the end of 2026 the exception is sales up to 10,000 PLN a month.