Hybrid invoice evidence / PDF-A/3
Validate the PDF/A-3 layer of a ZUGFeRD or Factur-X invoice
Inspect the hybrid PDF container separately from the CII business rules and make missing validator coverage visible.
Direct answer
Direct answer
A PDF/A-3 invoice validator should check that the file is actually a PDF, declares PDF/A part 3 and a conformance level, exposes the embedded-files name tree and AFRelationship metadata, and contains the expected factur-x.xml or ZUGFeRD-invoice.xml attachment name. Shipment Sentry performs those deterministic checks and runs veraPDF for full PDF/A conformance when the executable is installed. If it is absent, the result reports that gap instead of claiming compliance.
Why a parser is not enough
Hybrid e-invoices have two distinct artefacts: the human-readable PDF container and the structured invoice XML. Correct business totals cannot prove PDF/A-3 conformance, while a conforming PDF cannot prove EN 16931 business rules or equality between its visual and structured representations.
What the control should check
- 01Reject content without a PDF header.
- 02Require XMP metadata declaring pdfaid:part 3.
- 03Recognize conformance levels A, B or U.
- 04Inspect EmbeddedFiles and AFRelationship markers.
- 05Require the profile-appropriate XML attachment name.
- 06Run veraPDF when available and publish whether complete engine validation executed.
Working example
PDF header passed
pdfaid:part = 3 passed
pdfaid:conformance = B passed
AFRelationship passed
factur-x.xml passed
veraPDF PDF/A-3B executed / compliantWhen veraPDF is not installed, the final row is an explicit engine warning, never an inferred compliance pass.
Failure modes worth catching
- A normal PDF contains XML but is not PDF/A-3.
- The attachment exists without an associated-file relationship.
- The metadata claims conformance but veraPDF finds structural violations.
- A UI combines the XML score and PDF container result into a misleading single pass.
Put it into the dispatch workflow
- 1Upload the hybrid invoice PDF.
- 2Run structural container and embedded-file checks.
- 3Run veraPDF against the PDF/A-3 flavour when installed.
- 4Extract and validate the CII XML as a separate evidence layer.
- 5Resolve every container and business-rule error.
- 6Use the official profile artefacts and trading-party requirements before exchange.
Questions
Implementation answers
Can I upload a complete ZUGFeRD PDF?
Yes. The PDF/A-3 form is separate from the XML business-rule preflight and does not retain the uploaded PDF.
What happens if veraPDF is unavailable?
Deterministic marker checks still run, but the result states that full PDF/A validation did not execute.
Does it compare the visible PDF with the XML?
No. Visual-to-XML equality remains a separate control.
Sources and limits
Reviewed 2026-07-20. Public references cannot establish every partner-specific rule. Current implementation guides and agreements remain controlling.
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