Attestwire

Rule reference

BR-29 The invoicing period runs from "2026-07-31" (BT-73) to "2026-07-01" (BT-74), which ends before it starts

The invoicing period runs from "2026-07-31" (BT-73) to "2026-07-01" (BT-74), which ends before it starts. EN 16931 requires the end date to be later than or equal to the start date; equal is allowed, because a single-day period is a real thing. An inverted period is almost always two fields transposed, and it is worth catching here rather than downstream: a consumer that computes a duration from it gets a negative number and either books the accrual to the wrong period or divides by it.

This rule is implemented and its error payload below is real, but the long-form write-up — normative text, worked example, divergence note — is not written yet. Everything the library knows about this rule is on this page. Ask and we will prioritise it.

Business term
BT-73 / BT-74
Severity
fatal

What the library returns

The exact object in result.errors when this rule fires. Generated by running @attestwire/en16931, not transcribed:

TeachingError
{
  "rule": "BR-29",
  "field": [
    "BT-73",
    "BT-74"
  ],
  "severity": "fatal",
  "message": "The invoicing period runs from \"2026-07-31\" (BT-73) to \"2026-07-01\" (BT-74), which ends before it starts. EN 16931 requires the end date to be later than or equal to the start date; equal is allowed, because a single-day period is a real thing. An inverted period is almost always two fields transposed, and it is worth catching here rather than downstream: a consumer that computes a duration from it gets a negative number and either books the accrual to the wrong period or divides by it.",
  "fix": "Swap invoicingPeriod.startDate and invoicingPeriod.endDate, or correct whichever of the two is wrong. Use the same date in both fields for a period of one day.",
  "example": "\"invoicingPeriod\": { \"startDate\": \"2026-07-01\", \"endDate\": \"2026-07-31\" }",
  "xpath": "/ubl:Invoice/cac:InvoicePeriod/cbc:EndDate",
  "docsUrl": "https://attestwire.com/rules/BR-29"
}

xpath locates the element in the generated UBL document, which is where a KoSIT or Peppol validator will report the same problem.

A passing value

the shape this field expects
"invoicingPeriod": { "startDate": "2026-07-01", "endDate": "2026-07-31" }

The fix

Swap invoicingPeriod.startDate and invoicingPeriod.endDate, or correct whichever of the two is wrong. Use the same date in both fields for a period of one day.

All 292 rules →

Nearby: BR-30 — A line has an invoice line period running from "2026-07-31" (BT-134) to "2026-07-01" (BT-135), which ends before it starts; BR-28 — A line (id "1") has a negative item gross price (BT-148: -200); BR-31 — The document level allowance at allowances[0] has no usable allowance amount (BT-92): you supplied missing.

Check this rule against your invoice via the hosted API → https://api.attestwire.com/docs

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