Build the ordered syntax, semantic, national, security and authority checks needed for a selected country.
Readable bytes, expected extension, no truncation, stable SHA-256 evidence.
Parse and apply the relevant syntax schema: FA(3) XML.
Check invoice parties, dates, lines, taxes, totals, references and payment data.
KSeF/FA document signature · Polish NIP structure · Invoice totals and mandatory header fields
Validate national taxpayer and recipient identifiers.
Review QR, hash, signature or certificate requirements.
Submit or route through Authenticated KSeF 2.0 API or taxpayer application, with KSeF number, session/status handling, official receipt and offline-mode workflows. and preserve the official response.
Build the ordered validation layers needed for a country, from file integrity and syntax through security and official outcome.