bank.sx

{
  "name": "checkbalance",
  "base": "",
  "fields": [
    {
      "name": "contract",
      "type": "name"
    },
    {
      "name": "symcode",
      "type": "symbol_code"
    },
    {
      "name": "fee",
      "type": "asset"
    }
  ]
}