SERIES_FORMAT_NUM_REQUIRED
Variable {NUM} is required in the format. Sequential numbering is required by law
Category: Invoices
| HTTP status | 422 Unprocessable Content |
Example response
When this error occurs, the API answers 422 Unprocessable Content with a JSON body of this shape:
{
"type": "https://docs.beel.es/errors/SERIES_FORMAT_NUM_REQUIRED",
"title": "SERIES_FORMAT_NUM_REQUIRED",
"detail": "Variable {NUM} is required in the format. Sequential numbering is required by law",
"instance": "/v1/<resource>",
"errors": [],
"success": false,
"error": {
"code": "SERIES_FORMAT_NUM_REQUIRED",
"message": "Variable {NUM} is required in the format. Sequential numbering is required by law",
"details": {}
},
"meta": {
"timestamp": "2026-05-21T10:00:00Z",
"request_id": "4bf92f3577b34da6a3ce929d0e0e4736"
}
}The type URI is stable and always resolves to this page.
Message
Send the request with Accept-Language: <es|en|ca> to receive the message in your preferred language.
Other errors in this category
ATTACH_SOURCE_INVOICE_UNAVAILABLE
A source invoice is not available (it does not exist or you no longer have access); uncheck the source invoices attachment to send without the folder
ATTACH_SOURCE_INVOICES_NO_SOURCES
The invoice has no consolidation disbursements: there are no source invoices to attach
ATTACH_SOURCE_INVOICES_REQUIRES_PDF
Attaching the source invoices also requires attaching the invoice PDF
ATTACH_SOURCE_PDF_MISSING
These source invoices have no generated PDF: ‹value›
ATTACH_SOURCE_ZIP_TOO_LARGE
The source invoices ZIP (‹value› MB) exceeds the maximum sendable size (‹value› MB)
Keep exploring
SERIES_FORMAT_LOCKED_HAS_INVOICES
Cannot modify the series format because it has associated invoices. This would affect numbering integrity.
SERIES_FORMAT_NUMBER_TOO_LONG
The number this series generates can reach ‹value› characters and the AEAT accepts at most ‹value› (series and number together). Shorten the code or the fixed text of the format