Validation rules

BR-29 — EN 16931 rule

The invoicing period end date (BT-74) must not be earlier than its start date (BT-73).

Rule: BR-29 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-74 — Invoicing period end date
Field in your JSON: invoice.invoicing_period.end_date

How to fix it

Correct invoice.invoicing_period so end_date is on or after start_date.

BR-29 auf Deutsch — was bedeutet der Fehler?

Das Enddatum des Abrechnungszeitraums (BT-74) liegt vor dessen Startdatum (BT-73).

So beheben Sie den Fehler

Korrigieren Sie invoice.invoicing_period: end_date muss auf oder nach start_date liegen.

Related rules

BR-30 — An invoice line period end date (BT-135) must not be earlier than its start date (BT-134).
BR-28 — The item gross price (BT-148) must not be negative.
BR-27 — The item net price (BT-146) must not be negative.
BR-31 — A document-level allowance (BG-20) has no allowance amount (BT-92).
BR-32 — A document-level allowance needs a VAT category (BT-95); it cannot be inherited because the lines use more…
BR-26 — An invoice line has no item net price (BT-146).

Official sources

Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.

Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.