visibility Transparent check logic layers 3 core stages + extras auto_awesome EU AI optional, recommended

How Canary checks ZUGFeRD, Factur-X and e-invoices

This page explains how Canary checks ZUGFeRD, Factur-X and e-invoices, which data is compared, where automated comparison reaches its limits, and when AI+ adds additional value.

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Check flow: what is checked against what

Canary clearly separates standards validation, data comparison and context analysis. This shows which finding comes from which method.

rule 1) Technical validation (mandatory)

Checks embedded XML against ZUGFeRD/EN-16931 rules and structural mandatory fields. Outcome: formally valid/invalid plus rule findings.

compare_arrows 2) PDF↔XML comparison

Compares payment- and tax-relevant fields from PDF view with XML values (e.g. IBAN, amounts, tax rate, date, invoice number).

auto_awesome 3) AI+ context check (optional)

EU AI analyzes context and plausibility in the PDF, prioritizes candidates better and helps with ambiguities that pure numeric matching cannot solve reliably.

Core challenge in PDF comparisons

Automated matching is essential, but not trivial. Different layouts and text structures can represent the same values very differently.

Each issuer uses its own layout, labels and field ordering.
The same numeric value can appear multiple times in the PDF (line item, totals, hints, footer).
Date, currency and number formats vary strongly (e.g. 1.500,00 vs 1500.00).
Extracted PDF text can vary depending on generator, fonts or layered content.

Additional checks

In addition to the 3 core stages, Canary adds targeted extra checks when prerequisites are met.

policy Conflict audit

Looks for contradictory statements in PDF context and marks potential candidate conflicts transparently instead of assigning values silently wrong.

verified_user VIES/eVatR VAT-ID check

Checks VAT IDs only when required IDs and country constellation are available. If the service is down, the status is clearly shown as "currently unavailable".

Pragmatic recommendation

For robust decisions, use check results in this order:

Always run technical validation + PDF↔XML comparison.
Enable AI+ for open, critical or unclear fields.
For VAT-ID-relevant cases, treat VIES/eVatR status as an additional signal.

Canary provides a technical risk assessment for payment and booking processes. The final release decision remains an organizational responsibility.