Validation stack
How to validate KSeF FA(3)
- 1File integrity and parsing
Preserve the source bytes and hash, then confirm the file is readable and well formed.
- 2Syntax and profile
Apply the correct schema and profile identifiers for FA(3) XML.
- 3Semantic business rules
Validate parties, dates, lines, taxes, totals, references and payment data.
- 4National and network rules
KSeF/FA document signature · Polish NIP structure · Invoice totals and mandatory header fields
- 5Identity, security and routing
Confirm national identities, signatures, hashes, QR and recipient routing as applicable.
- 6Official outcome
Use Authenticated KSeF 2.0 API or taxpayer application, with KSeF number, session/status handling, official receipt and offline-mode workflows. and preserve the response from KSeF FA(3).