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Compliant e-invoices in one POST request. Generate, validate and parse XRechnung and ZUGFeRD / Factur-X. Made in Germany, hosted in the EU.

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© 2026 VIBOA UG (haftungsbeschränkt) · HannoverDE · EN

Not legal or tax advice. XRechnung® is a standard of KoSIT; ZUGFeRD® of FeRD. Names used for format identification only.

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API referencePOST…/generatePOST…/validatePOST…/parse
ReferenceError codesValidation rulesInteractive referenceOpenAPI spec↗

API errors

The document could not be parsed

The XML sent to /v1/invoices/parse could not be mapped to the invoice model. Nothing was processed or billed.

Error type
https://normbill.com/docs/errors/unparseable-document
HTTP status
400

Common causes

  • The document is not well-formed XML, or carries a DOCTYPE/DTD declaration (rejected as an XXE vector).
  • The root element is not a UBL 2.1 <Invoice> — CII documents (ZUGFeRD/Factur-X) are not supported yet, and UBL CreditNote roots are rejected (XRechnung expresses credit notes as an Invoice with type code 381).
  • The CustomizationID (BT-24) is missing or names a specification normbill does not support.
  • The document is missing fields the invoice model requires (for example the seller name) — the detail lists each JSON path.

How to fix it

  • Check the detail field: it names the exact element or JSON path that failed.
  • Confirm the document is an XRechnung UBL invoice — CII/ZUGFeRD parsing lands with the hybrid-PDF milestone.
  • If a legally valid XRechnung fails to parse, that is a bug on our side — send the rule id and document structure (never real invoice data) to support.

The error response format

Every non-2xx response from the API is an RFC 9457 problem-details body (application/problem+json) with at least type, title, status and detail. The type URL links back to this reference.

All error slugs: invalid-request, bad-request, payload-too-large, unauthorized, validation-failed, unparseable-document, plan-limit, quota-exceeded, rate-limited, overage-cap-reached, validate-fair-use, idempotency-key-invalid, idempotency-key-reuse, idempotency-conflict, pdf-unavailable, validator-unavailable, not-ready. Still stuck? Email support@normbill.com or start at the docs overview.