curl --request POST \
  --url https://api.gcore.com/iam/admin/paid_features \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "client_id": 123,
  "feature_id": 123,
  "feature": {
    "service": "CDN"
  }
}
'

{
  "id": 123,
  "client_id": 123,
  "feature_id": 123,
  "feature": {
    "id": 123,
    "name": "<string>",
    "service": "CDN",
    "is_free": true
  },
  "created_date": "2023-11-07T05:31:56Z"
}