curl --request POST \
  --url https://api.walletsuite.io/api/approvals/allowance \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "chain": "<string>",
  "owner": "<string>",
  "tokenContract": "<string>",
  "spender": "<string>"
}
'

{
  "ok": true,
  "code": "<string>",
  "message": "<string>",
  "data": {
    "chain": "<string>",
    "owner": "<string>",
    "tokenContract": "<string>",
    "spender": "<string>",
    "allowance": 123,
    "updatedAt": "2023-11-07T05:31:56Z"
  }
}