ErrorsAll codes
SERIES_FORMAT_LOWERCASE_VARS
Lowercase variables detected: {0}. Variables must be UPPERCASE (e.g., {CODIGO}, {YYYY}, {MM}, {NUM})
Category: Invoices
Example response
When this error occurs, the API returns a JSON response with the following shape:
{
"type": "https://docs.beel.es/errors/SERIES_FORMAT_LOWERCASE_VARS",
"title": "SERIES_FORMAT_LOWERCASE_VARS",
"detail": "Lowercase variables detected: {0}. Variables must be UPPERCASE (e.g., {CODIGO}, {YYYY}, {MM}, {NUM})",
"instance": "/v1/<resource>",
"errors": [],
"success": false,
"error": {
"code": "SERIES_FORMAT_LOWERCASE_VARS",
"message": "Lowercase variables detected: {0}. Variables must be UPPERCASE (e.g., {CODIGO}, {YYYY}, {MM}, {NUM})",
"details": {}
},
"meta": {
"timestamp": "2026-05-21T10:00:00Z",
"request_id": "4bf92f3577b34da6a3ce929d0e0e4736"
}
}The type URI is stable and always resolves to this page.
Message
Lowercase variables detected: {0}. Variables must be UPPERCASE (e.g., {CODIGO}, {YYYY}, {MM}, {NUM})
Variables en minúsculas detectadas: {0}. Las variables deben estar en MAYÚSCULAS (ej: {CODIGO}, {YYYY}, {MM}, {NUM})
Variables en minúscules detectades: {0}. Les variables han d''estar en MAJÚSCULES (ex: {CODIGO}, {YYYY}, {MM}, {NUM})
Send the request with Accept-Language: <es|en|ca> to receive the message in your preferred language.
Tokens like
{0}are runtime arguments — the backend fills them with actual values before responding.
Other errors in this category
BULK_PDF_ERROR
Error processing bulk PDF download
CANCELLATION_VIA_SPECIFIC_ENDPOINT
To cancel an invoice use the specific cancellation endpoint
CANNOT_DUPLICATE_DELETED_INVOICE
Cannot duplicate a deleted invoice
CLIENT_NOT_FOUND
Customer not found: {0}
DELETION_FAILED
Error deleting the invoice