curl --location --request POST 'https://api.kfim.cn/merchant_gate/merchant_secret_free' \
--data-urlencode 'return_url=' \
--data-urlencode 'notify_url=' \
--data-urlencode 'business_code=' \
--data-urlencode 'mch_num=' \
--data-urlencode 'timestamp=' \
--data-urlencode 'sign='
{
"code": 0,
"msg": "string",
"data": {
"request_no": "string",
"status": 0
}
}