curl --request POST \
  --url https://whitebit.com/api/v4/mining/payout-destination \
  --header 'Content-Type: application/json' \
  --header 'X-TXC-APIKEY: <api-key>' \
  --data '
{
  "accountName": "my_miner_01"
}
'

{
  "payoutDestination": "main_balance",
  "externalAddress": null
}