7 PDF-to-XML KSeF Conversion Errors
Learn the most common errors when converting a PDF invoice to FA(3) XML, their effects in KSeF and how to catch them before submission.
GuideJune 21, 2026
Guide
KSeFGPT guide: practical articles on KSeF, FA(3), XML, deadlines, invoice errors and automation for companies and accounting teams.
Articles and instructions
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Missing UPO in KSeF: how to download the official receipt?
Cannot see UPO after submitting an invoice to KSeF? Check status, KSeF number, session, rejection errors and UPO download paths in the app, API or KSeFGPT.
GuideJune 19, 2026
KSeF for small businesses. How to choose an invoice and accounting-work application in 2026
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.
GuideJune 18, 2026
PDF to XML converters for KSeF 2026 compared - which one should you choose?
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.
GuideJune 10, 2026
Invoice rejected by KSeF? Common errors and how to fix them
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.
GuideJune 7, 2026
How to generate a KSeF certificate
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.
GuideJune 6, 2026
How to migrate a customer database during KSeF implementation
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.
GuideJune 3, 2026
How to receive an invoice from KSeF step by step
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.
GuideJune 1, 2026
What to do when an invoice for a purchase you did not make appears in KSeF?
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.
GuideJune 1, 2026
KSeF: What to Do When the Mobile App Is Not Working
Check whether the issue is your phone, login, permissions or KSeF availability. See safe steps and fallback options.
Guide31 May 2026
KSeF Invoice Issue Date and Payment Term: When to Count Invoice Delivery From?
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.
Guide29 May 2026
How to send many invoices to KSeF from Excel
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.
Guide20 May 2026