Data and files
JPK and KSeF invoice viewer — open the XML and see what is inside
JPK files and structured invoices are machine formats: tens of thousands of lines of XML in which neither the totals nor the errors are visible to the naked eye. This tool turns them into a table, computes the summaries and flags anomalies - invalid tax IDs, repeated document numbers, mismatched totals. The result exports to CSV and opens in Excel.
Free · no signup · runs in your browser
Drag an XML file here, or click to choose one
JPK_V7, JPK_FA or a KSeF invoice in the FA(3) structure. The file is read in your browser and never uploaded.
How it works
- 01
Upload the XML file
We detect automatically whether it is a JPK_V7, a JPK_FA, or a single KSeF invoice in the FA(3) structure.
- 02
The file is unpacked into a table
Header, line items, counterparties, amounts and dates. All readable, with totals under every numeric column.
- 03
We check for anomalies and you export the result
Failed tax ID checksums, duplicated document numbers, outlier amounts and gaps in required fields. The table downloads as CSV.
Assumptions and limits
- The file is parsed entirely in your browser. It is never sent to any server or stored by us - and JPK files contain full counterparty data, so this is not a detail.
- This is not an XSD schema validator. We do not check conformance with the Ministry of Finance pattern - dedicated validators exist for that. This tool answers a different question: what is actually in this file and does the data inside make sense.
- The FA(3) structure has applied in KSeF since 1 February 2026. Older FA(2) files will still open, but some fields may not be recognised.
- Detected anomalies are signals, not formal errors. A repeated document number may be a legitimate correction, and an outlier amount may simply be a large order.
- Totals are computed from the line items in the file and compared with the totals declared in the header. A discrepancy between them usually signals that the file was generated from incomplete data.
Frequently asked questions
Is this an XSD validator for KSeF? +
No. Schema validators check conformance with the Ministry of Finance pattern and there are plenty of them. This tool answers a different question: what is inside the file and whether the data makes business sense. Both checks are useful, for different things.
Is a JPK file with my counterparty data safe here? +
Yes - the file is read only in your browser and never leaves your device. Load the page, disconnect from the internet and drop the file in to see for yourself.
Which files do you support? +
JPK_V7 (V7M and V7K), JPK_FA and single KSeF invoices in the FA(3) structure. Older FA(2) files will open too, though some fields may not be recognised.
The line item total does not match the header total - what does that mean? +
Usually that the file was generated from incomplete data, or that some items round differently. It is a signal to check the system that produced the file - before it reaches the tax office.
Can you automate this checking for us? +
Yes. Checking files before submission is a standard part of an integration with e-invoicing or an accounting system. You get a ballpark instantly in our quote calculator and a reply from a human within 24 hours.
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