curl --request POST \
  --url https://openplatform.gateapi.io/transfer/open/institution/v1/pay/convert/preview \
  --header 'Content-Type: application/json' \
  --header 'X-GatePay-Certificate-ClientId: <x-gatepay-certificate-clientid>' \
  --header 'X-GatePay-Nonce: <x-gatepay-nonce>' \
  --header 'X-GatePay-On-Behalf-Of: <x-gatepay-on-behalf-of>' \
  --header 'X-GatePay-Signature: <x-gatepay-signature>' \
  --header 'X-GatePay-Timestamp: <x-gatepay-timestamp>' \
  --data '
{
  "buyCurrency": "<string>",
  "sellCurrency": "<string>"
}
'

{
  "status": "<string>",
  "code": "<string>",
  "errorMessage": "<string>",
  "data": {
    "sellCurrency": "<string>",
    "buyCurrency": "<string>",
    "sellAmount": "<string>",
    "buyAmount": "<string>",
    "rate": "<string>",
    "quoteId": "<string>"
  }
}