curl --request POST \
  --url https://api.joinslash.com/transfer/virtual-account \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --header 'X-Idempotency-Key: <x-idempotency-key>' \
  --data '{
  "source": "<string>",
  "destination": "<string>",
  "amountCents": 123
}'

{
  "transferId": "<string>"
}