ksefuj

Free browser-based validator for Polish KSeF FA(3) e-invoices

WebfreePoland

ksefuj is a free, open-source validator for Poland's KSeF FA(3) e-invoice format, checking documents against the official schema and semantic rules directly in the browser, with a CLI and npm package for automated workflows. It's aimed at Polish businesses and developers who need to catch invoice errors before submitting to KSeF.

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