curl --request POST \
  --url 'https://domain.hostwithdothost.com/?action=checkbalance' \
  --header 'Content-Type: application/json' \
  --data '{
  "username": "your_username",
  "password": "your_password"
}'

{
  "ErrorCode": 0,
  "OperationMessage": "Command completed succesfully.",
  "OperationResult": "SUCCESS",
  "Balance": "1.02",
  "CurrencyId": 2,
  "CurrencyInfo": null,
  "CurrencyName": "USD",
  "CurrencySymbol": "$"
}