# 1. Fiat-to-cryptocurrency exchange

Request method

POST

URL：

/api/v1/exchange/express/trade/buy

Content-Type：

Content-Type: application/json; charset=utf-8

Request header parameters (Header)

Param	Type	Description	Sample
access_key	String	Access key obtained from the merchant backend	pFqV75X3
timestamp	int64	Unix millisecond timestamp (13 digits)	1679724896223
nonce	String	UUID V4 random string	794c26b0-d33c-4394-b2bb-c485eca16d9e
sign	String	The signature calculated by the signature algorithm	kAXyh+eerqrefyaF8dyFB0M4FVo=

All the above parameters are passed as HTTP Header

Request body data example: INR

{
    "externalOrderId": "20250513184347329830",
    "chainType": "BSC",
    "tokenType": "USDT",
    "addressTo": "0xa8666442fA7583F783a169CC9F3333333360295E8",
    "tokenAmount": "1",
    "currencyType": "INR",
    "payType": "BANK",
    "remark": "test",
    "notifyUrl" : ""
}

Parameter Description:

Parameter name	type	Is this field required?	describe
tokenAmount	Decimal	yes	Token Amount
externalOrderId	String	yes	Merchant order number
chainType	String	yes	Chain type BSC
tokenType	String	yes	Token Type USDT
addressTo	String	yes	address
currencyType	String	yes	Currency Type INR
payType	string	yes	Payment type: BANK UPI
notifyUrl	String	no	Callback address after payment is completed (server side)
remark	String	no	Merchant customized remarks

Response type:

Header: { 'Content-Type': 'application/json;charset=utf-8'}

Create a payment response description:

Normal response data example (HTTP 200)

{
    "code": "200",
    "success": true,
    "msg" : "Success" ,
    "msgEn": "SUCCESS",
    "data": {
        "chainType": "BSC",
        "currencyAmount": "83.2309",
        "tokenAmount": "1",
        "currencyType": "INR",
        "tokenType": "USDT",
        "externalOrderId": "20250513184347329830",
        "orderId": "OEXCHEXCH202505131043481747133028307HAMBIT-U0000000401298824",
        "tradeType": "BUY",
        "payUrl": null,
        "exchangePrice": "83.2309",
        "orderFee": "0.0118",
        "bankAccountNumber": null,
        "bankAccountType" : null ,
        "bankCode" : null ,
        "bankName" : null ,
        "cashierUrl": "http://fiat/OEXCHEXCH202505131043481747133028307-U0000000401298824"
    }
}

Response Parameter Description

Parameter name	type	describe
chainType	String	Main Chain
currencyAmount	String	Amount in Fiat Currency
tokenAmount	String	Token Amount
currencyType	String	Fiat currency type
tokenType	String	Token Type
externalOrderId	String	Merchant order number
orderId	String	Order Number
tradeType	String	Transaction Type
payUrl	String	Fiat currency payment link(to be used according to actual situation)
BankAccountNumber	String	Channel Bank Account Number(to be used according to actual situation)
exchangePrice	String	exchange rate
orderFee	String	Fees
BankAccountType	String	Channel bank account type (to be used according to actual situation)
BankCode	String	Channel bank code (use according to actual situation)
BankName	String	Channel bank name (use according to actual situation)
cashierUrl	String	Redeem cashier link

Request body data example: BRL

{
    "externalOrderId": "20250513192309317184",
    "chainType": "BSC",
    "tokenType": "USDT",
    "addressTo": "0xa8666442fA7583F783a169CC9F5449333333395E8",
    "tokenAmount": "10.214234221423422312",
    "currencyType": "BRL",
    "payType": "PIX",
    "remark": "test",
    "notifyUrl" : ""
}