curl --request POST \
  --url https://api.shoppex.io/dev/v1/products/{id}/variants/fields/{fieldId}/options \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "label": "United States",
  "value": "us",
  "sort_order": 1
}
'

{
  "data": {}
}