WeChat Pay Go

WeChat Pay API v3 Go SDK - Simple and efficient WeChat Pay client implementation

Features

• ✅ WeChat Pay API v3 support
• ✅ Automatic signature and verification
• ✅ Automatic certificate serial number calculation
• ✅ JSAPI order, query, refund and more
• ✅ Zero dependencies, Go standard library only

Installation

go get github.com/lsongdev/wechatpay-go

Quick Start

1. Initialize Config

package main

import (
    "fmt"
    "github.com/lsongdev/wechatpay-go/wechatpay"
)

func main() {
    cfg := &wechatpay.Config{
        API:      "https://api.mch.weixin.qq.com",
        AppID:    "wxd2520e2febed3ac2",
        MchID:    "1105155963",
        APIV3Key: "45a0a3b80364857f0a1d5fc7bc2cc2e3", // 32-byte key
    }

    // Load certificate
    err := cfg.LoadCert("./apiclient_key.pem", "./apiclient_cert.pem")
    if err != nil {
        panic(err)
    }

    // Create client
    client, err := wechatpay.NewWeChatPay(cfg)
    if err != nil {
        panic(err)
    }

    // Create order
    order := &wechatpay.OrderRequest{
        Description: "Test Order",
        OutTradeNo:  "1234567890",
        NotifyUrl:   "https://www.example.com/notify",
        Amount: wechatpay.OrderAmount{
            Total:    100, // smallest currency unit
            Currency: "CNY",
        },
    }

    resp, err := client.CreateOrder(order)
    if err != nil {
        panic(err)
    }

    fmt.Println("Code URL:", resp.CodeUrl)
}

2. Query Order

// Query by out trade number
trade, err := client.QueryByOutTradeNo("1234567890")
if err != nil {
    panic(err)
}
fmt.Println("Trade State:", trade.TradeState)
fmt.Println("Trade State Desc:", trade.TradeStateDesc)

// Query by WeChat Pay transaction ID
trade, err = client.QueryByTransactionId("4200001234567890")

3. Close Order

err := client.CloseOrder("1234567890")
if err != nil {
    panic(err)
}

4. Refund

refund := &wechatpay.RefundRequest{
    OutTradeNo:  "1234567890",
    OutRefundNo: "refund_1234567890",
    Amount: wechatpay.RefundAmount{
        Refund:   100, // refund amount in cents
        Total:    100, // order amount in cents
        Currency: "CNY",
        From: []wechatpay.RefundFrom{
            {Account: "AVAILABLE", Amount: 100},
        },
    },
    Reason: "User requested refund",
}

resp, err := client.Refund(refund)
if err != nil {
    panic(err)
}
fmt.Println("Refund ID:", resp.RefundId)
fmt.Println("Refund Status:", resp.Status)

Config Reference

Config Struct

Field	Type	Description
API	string	WeChat Pay API URL
AppID	string	Official Account/Mini Program AppID
MchID	string	Merchant ID
APIV3Key	string	API v3 key (32 bytes)
PrivateKey	string	Merchant private key (PEM format)
MchCert	string	Merchant certificate (PEM format)

LoadCert Method

Loads private key and certificate from specified paths and automatically sets them to Config. Certificate serial number is automatically calculated when creating the client.

Order Status

Status	Description
SUCCESS	Payment successful
REFUND	Refunded
NOTPAY	Not paid
CLOSED	Closed
REVOKED	Revoked
USERPAYING	User paying
PAYERROR	Payment failed

Error Handling

SDK returns errors with the following structure:

type ErrorMessage struct {
    Code    string `json:"code"`
    Message string `json:"message"`
}

Example:

resp, err := client.CreateOrder(order)
if err != nil {
    // Handle error
    fmt.Println("Error:", err)
}

Examples

For complete example code, see examples/ directory.

Documentation Links

• WeChat Pay API v3 Documentation
• JSAPI Order Interface
• Query Order Interface
• Apply for Refund Interface

License

Apache License 2.0