Practical knowledge on KSeF - from integration basics to AI-driven invoice automation. Written from real deployments, not theory.
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Ask about a topicFrequently asked questions (FAQ)
Short answers about the KSeFGPT app and about the National e-Invoice System itself, with links to the full articles.
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A practical guide for businesses and accounting teams: where to find incoming invoices in KSeF, when they are considered received, how often to check them and what to do after retrieval.
Learn how to distinguish a wrong NIP from a suspected scam invoice, when to contact the seller, when to request a correction and how to report abuse in the KSeF 2.0 Taxpayer Application.
Check whether the issue is your phone, login, permissions or KSeF availability. See safe steps and fallback options.
Check when a KSeF invoice is deemed received, how to distinguish the issue date from the KSeF number date and why the payment term still follows from the contract and commercial transaction rules.
A practical scenario for restaurants, catering and chains: B2B invoices, receipts with NIP, suppliers, corrections, UPO and document-flow control.
Learn when an invoice outside KSeF is an exemption, when it is an offline mode and when it becomes a compliance risk.
A practical guide for companies and accounting teams: how to prepare an invoice in KSeFGPT with AI chat, check Preview, PDF and FA(3) XML, and manually approve submission to KSeF.
See which 2026 transitional rules are expected to expire, when KSeF will cover the smallest taxpayers, and how to distinguish a receipt with NIP from a simplified invoice.
A practical guide: how to prepare an XLSX sheet, map columns to FA(3) fields, check errors and send valid invoices to KSeF in KSeFGPT.
Learn what UPO means in KSeF, what it contains, when it can be downloaded, how it differs from the KSeF number and why the Polish official term is Urzędowe Poświadczenie Odbioru.
Free invoice submission to KSeF in 2026: Taxpayer Application KSeF 2.0, e-mikrofirma, KSeF mobile app, KSeFGPT public free tools and a hybrid workflow.
Correction to zero, manual line-item editing, correction from XML and correction from the KSeF invoice list. See how to prepare a corrective invoice in KSeFGPT.