Call Payment

Update Time：2025.01.07

the merchant server first calls the [Order Placement API] to generate a prepayment order, and signs the obtained parameter prepay_id again before transferring it to the app to initiate payment.

1. API intro

Applicable object： Common mode Institutional mode

2. Request Parameters

This API signature has no background interface interaction, and the data in the list shall be signed

the client request field （Note: The following field names are case sensitive）：

Name	Variable Name	Type	Required	Description
APPID	appId	string[1,16]	Yes	APPID corresponding to the mobile app applied by the merchant on the WeChat Open Platform Example: wx8888888888888888
Merchant ID	partnerid	string[1,32]	Yes	Merchant ID assigned by WeChat Pay. Example: 1900000109
Prepayment transaction session	prepayid	string[1,64]	Yes	Prepayment session ID generated by WeChat, which is used in subsequent API calls. The value is valid for 2 hours. Example: WX1217752501201407033233368018
An extension string for order details	package	string[1,128]	Yes	Specify as the static value “Sign=WXPay” Example: Sign=WXPay
Random string	noncestr	string[1,32]	Yes	Random string, not longer than 32 digits. It is recommended to use the random number generation algorithm. Example: 5K8264ILTKCH16CQ2502SI8ZNMTM67VS
Timestamp	timestamp	string[1,10]	Yes	The current time. For details, see timestamp rules. Example: 1412000000
Signature	paySign	string[1,64]	Yes	Signature. For more information, see the paySign generation rules. Example: C380BEC2BFD727A4B6845133519F3AD6

3. paySign Generating Rules

3.1.Construct a signature string

There are four lines in the signature string, and each line is a parameter. Each line ends with \n (Newline character; the ASCII code value is 0x0A), and even the last line shall ends with \n. If the parameter itself ends with \n, an additional \n is also required

Signature fields and formats:

1   Account ID 
2   Timestamp
3   Random string
4   Prepayment transaction session

Example of a string to be signed：

1   wx8888888888888888
2   1414561699
3   5K8264ILTKch16CQ2502SI8ZNMTM67VS
4   123456789

3.2. Calculating signature value：

The signature method is the same as the signature for request data. Use the merchant private key to sign the string using the SHA256-with-RSA signature algorithm, and obtain the signature value through Base64 encoding.

1$ echo -n -e \
2"wx8888888888888888\n1414561699\n5K8264ILTKCH16CQ2502SI8ZNMTM67VS\nwx201410272009395522657a690389285100\n" \
3  | openssl dgst -sha256 -sign apiclient_key.pem \
4  | openssl base64 -A
5  uOVRnA4qG/MNnYzdQxJanN+zU+lTgIcnU9BxGw5dKjK+VdEUz2FeIoC+D5sB/LN+nGzX3hfZg6r5wT1pl2ZobmIc6p0ldN7J6yDgUzbX8Uk3sD4a4eZVPTBvqNDoUqcYMlZ9uuDdCvNv4TM3c1WzsXUrExwVkI1XO5jCNbgDJ25nkT/c1gIFvqoogl7MdSFGc4W4xZsqCItnqbypR3RuGIlR9h9vlRsy7zJR9PBI83X8alLDIfR1ukt1P7tMnmogZ0cuDY8cZsd8ZlCgLadmvej58SLsIkVxFJ8XyUgx9FmutKSYTmYtWBZ0+tNvfGmbXU7cob8H/4nLBiCwIUFluw==

The sample code is as follows:

IOS

1PayReq *request = [[[PayReq alloc] init] autorelease];
2request.partnerId = @"10000100";
3request.prepayId= @"1101000000140415649af9fc314aa427";
4request.package = @"Sign=WXPay";
5request.nonceStr= @"a462b76e7436e98e0ed6e13c64b4fd1c";
6request.timeStamp= @"1397527777";
7request.sign= @"oR9d8PuhnIc+YZ8cBHFCwfgpaK9gd7vaRvkYD7rthRAZ\/X+QBhcCYL21N7cHCTUxbQ+EAt6Uy+lwSN22f5YZvI45MLko8Pfso0jm46v5hqcVwrk6uddkGuT+Cdvu4WBqDzaDjnNa5UK3GfE1Wfl2gHxIIY5lLdUgWFts17D4WuolLLkiFZV+JSHMvH7eaLdT9N5GBovBwu5yYKUR7skR8Fu+LozcSqQixnlEZUfyE55feLOQTUYzLmR9pNtPbPsu6WVhbNHMS3Ss2+AehHvz+n64GDmXxbX++IOBvm2olHu3PsOUGRwhudhVf7UcGcunXt8cqNjKNqZLhLw4jq\/xDg==";
8[WXApi sendReq：request];

Android

1IWXAPI api;
2PayReq request = new PayReq();
3request.appId = "wxd930ea5d5a258f4f";
4request.partnerId = "1900000109";
5request.prepayId= "1101000000140415649af9fc314aa427",;
6request.packageValue = "Sign=WXPay";
7request.nonceStr= "1101000000140429eb40476f8896f4c9";
8request.timeStamp= "1398746574";
9request.sign= "oR9d8PuhnIc+YZ8cBHFCwfgpaK9gd7vaRvkYDSs2+AehHvz+n64GDmXxbX++IOBvm2olHu3PsOUGRwhudhVf7UcGcunXt8cqNjKNqZLhLw4jq\/xDg==";
10api.sendReq(request);

HarmonyOS Next

1IWXAPI api;
2let req = new wxopensdk.PayReq
3req.appId = 'wxd930ea5d5a258f4f'
4req.partnerId = '1900000109'
5req.prepayId = '1101000000140415649af9fc314aa427'
6req.packageValue = 'Sign=WXPay'
7req.nonceStr = '1101000000140429eb40476f8896f4c9'
8req.timeStamp = '1398746574'
9req.sign = 'oR9d8PuhnIc+YZ8cBHFCwfgpaK9gd7vaRvkYD7rthRAZ\/X+QBhcCYL21N7cHCTUxbQ+EAt6Uy+lwSN22f5YZvI45MLko8Pfso0jm46v5hqcVwrk6uddkGuT+Cdvu4WBqDzaDjnNa5UK3GfE1Wfl2gHxIIY5lLdUgWFts17D4WuolLLkiFZV+JSHMvH7eaLdT9N5GBovBwu5yYKUR7skR8Fu+LozcSqQixnlEZUfyE55feLOQTUYzLmR9pNtPbPsu6WVhbNHMS3Ss2+AehHvz+n64GDmXxbX++IOBvm2olHu3PsOUGRwhudhVf7UcGcunXt8cqNjKNqZLhLw4jq\/xDg=='