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 small businesses, sole proprietors and microbusinesses: KSeF deadlines, purchase invoice receipt, UPO, KSeF number, XML FA(3), official MF tools and KSeFGPT.
How a translated PDF visualization differs from FA(3) XML, the KSeF number and UPO, and how to share an invoice with a foreign counterparty without creating a second document.
How to prepare an invoice for a German counterparty in KSeFGPT, verify DE and VAT EU data, send FA(3) XML to KSeF and generate a German-language informational PDF visualization.
How to send a readable document version to a counterparty without creating a second invoice. KSeFGPT lets you download an incoming or outgoing invoice as an informational visualization in Polish, English, German or Ukrainian.
A practical guide for accountants, accounting offices and CFOs: where AI shortens document work, where it requires human control and how to assess a tool for KSeF, GDPR and the AI Act.
Not every PDF to XML converter is suitable for KSeF. Check when to choose KSeFGPT, the Taxpayer Application, an ERP, ksefpdf.pl or another tool, and why regular XML from a PDF is not enough.
Learn how to open an FA(3) XML file, find invoice data, the KSeF number, tax IDs, line items and amounts, and when to use a validator or XML-to-PDF converter.
Find out why KSeF rejected an invoice, how to read its status, correct P_1, FA(3) XML, permissions or a duplicate, and safely submit it again.
KSeF does not replace JPK_VAT. Learn the differences between FA(3), JPK_V7M, JPK_V7K and JPK_FA, and the rules for KSeF numbers, corrections and offline modes.
An up-to-date guide to the KSeF 2.0 Taxpayer Application: choosing a certificate purpose, generating the private .key file, downloading the .crt file, and securely preparing the complete set for use.
A practical guide for companies that want to move customers and contractors from an old system, Excel, CSV or Fakturownia.pl before KSeF go-live without carrying over duplicates and errors.
Structured invoices can become a clean source of customer and supplier data. See which fields to collect, how to avoid duplicates and where the KSeFGPT Counterparties module fits into the process.