curl --request POST \
  --url https://{host}/remuneration/api/variable-items \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: application/json' \
  --data '{
  "amount": 123,
  "natureId": 123,
  "workContractId": 123,
  "amendmentId": 0,
  "comments": "For outstanding performance this quarter",
  "period": "2023-12-25"
}'

{
  "amount": 123,
  "natureId": 123,
  "workContractId": 123,
  "amendmentId": 0,
  "comments": "For outstanding performance this quarter",
  "period": "2023-12-25",
  "id": 123,
  "nature": {
    "id": 123,
    "name": "Annual bonus",
    "type": "Amount",
    "category": {
      "id": 123,
      "code": "BONUS"
    },
    "establishments": [
      {
        "id": 123,
        "name": "Lucca FR",
        "currencyCode": "EUR",
        "currencySymbol": "€"
      }
    ]
  },
  "workContract": {
    "workContractId": 123,
    "amendmentId": 123,
    "ownerId": 123,
    "owner": {
      "id": 123,
      "firstName": "<string>",
      "lastName": "<string>",
      "name": "<string>",
      "displayName": "<string>"
    },
    "startsOn": "2023-12-25",
    "endsOn": "2023-12-25"
  },
  "isDeleted": true
}