Review your Invoice XML structure and correct the issue described by this rule. Check relevant cbc: and cac: elements per CIUS-AT (Austria). You can also use Invoice Navigator's compliance engine to correct this automatically in your pipeline.

Is AT-01 a critical error?

AT-01 is a warning that may not always cause rejection, but indicates a compliance issue.

Can AT-01 be automatically fixed?

Many instances of AT-01 can be automatically corrected using Invoice Navigator's compliance engine. The fix is applied in your pipeline with full audit evidence.

warningAUTCIUS-AT (Austria)

`AT-01`:Austrian sellers should include UID number

Austrian sellers should include UID number. This validation rule ensures Invoice compliance with CIUS-AT (Austria).

Severity

Warning

Rule set

CIUS-AT (Austria)

Country

AUT

Fix type

BLOCKED

Engine Classification

Financial or legal field · Modification blocked by policy

What is AT-01?

AT-01 is a warning validation rule defined in the CIUS-AT (Austria) specification (AUT national rules). It checks whether austrian sellers should include uid number.

This is a soft validation failure. The invoice may pass initial transmission, but non-compliant values in this field can cause problems during tax audits, buyer-side processing, or downstream VAT reconciliation.

This error requires manual correction — financial fields are protected by policy.Test This Error ↓

Why This Error Matters

Austrian e-invoicing regulations require this for legal compliance. Invoices missing this information may be rejected by Austrian government portals and business partners.

AT-01 is a soft failure. The invoice may pass initial validation, but the non-compliant field can cause issues at the receiving end — tax authorities may flag it during audits, buyer ERP systems may fail to process it, or VAT reconciliation may produce mismatches. Fixing warnings before they accumulate prevents larger compliance gaps.

Validator Behavior

·Generates validation warning
·Error returned: AT-01
·Specification: CIUS-AT (Austria)

Before / After

Failing XML

<Invoice>
  <!-- Issue: Austrian sellers should include UID number -->
</Invoice>

Corrected XML

<Invoice>
  <!-- Issue resolved per CIUS-AT (Austria) -->
</Invoice>

Technical Reference

SpecCIUS-AT (Austria)

Seeing this in production? The API handles AT-01 automatically. See the fix response →

Related Errors

AT-R-002

Austrian UID number format invalid

AT-R-003

Austrian postal code format

Last updated: 27 February 2026

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Handle AT-01 Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.

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AT-01:Austrian sellers should include UID number