Attestwire

Rule reference

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

Line 1 has an invoice line period running from "2026-07-31" (BT-134) to "2026-07-01" (BT-135), which ends before it starts. The end must be later than or equal to the start; a single-day period with both dates equal is fine. Line periods are the field most often built by slicing a billing run programmatically, which is exactly the code path where an off-by-one on the boundary produces an inverted period rather than an obviously wrong one.

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-134 / BT-135
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-30",
  "field": [
    "BT-134",
    "BT-135"
  ],
  "severity": "fatal",
  "message": "Line 1 has an invoice line period running from \"2026-07-31\" (BT-134) to \"2026-07-01\" (BT-135), which ends before it starts. The end must be later than or equal to the start; a single-day period with both dates equal is fine. Line periods are the field most often built by slicing a billing run programmatically, which is exactly the code path where an off-by-one on the boundary produces an inverted period rather than an obviously wrong one.",
  "fix": "Swap line.period.startDate and line.period.endDate, or correct whichever is wrong. Check the loop that generates the slice if several lines are affected.",
  "example": "\"period\": { \"startDate\": \"2026-07-01\", \"endDate\": \"2026-07-15\" }",
  "xpath": "/ubl:Invoice/cac:InvoiceLine[1]/cac:InvoicePeriod/cbc:EndDate",
  "docsUrl": "https://attestwire.com/rules/BR-30"
}

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
"period": { "startDate": "2026-07-01", "endDate": "2026-07-15" }

The fix

Swap line.period.startDate and line.period.endDate, or correct whichever is wrong. Check the loop that generates the slice if several lines are affected.

All 292 rules →

Nearby: BR-31 — The document level allowance at allowances[0] has no usable allowance amount (BT-92): you supplied missing; BR-29 — The invoicing period runs from "2026-07-31" (BT-73) to "2026-07-01" (BT-74), which ends before it starts; BR-32 — The document level allowance at allowances[0] has no VAT category code (BT-95): you supplied missing.

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

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