SDK Guide

Updated: 9/16/26, 11:08:10 AM

Overview

DaxPay provides official signing SDKs for the open Payment API (/unipay/*). They encapsulate request signing, response verification and callback verification, so you don't have to implement the Signature Mechanism by hand. The Go / Java / Node.js / PHP / Python SDKs share the same contract and golden test vectors — their behavior is byte-for-byte identical.

Every SDK needs only two keys:

Key	Purpose	Source
Merchant private key (`privateKey`)	Sign requests	You generate an RSA key pair and keep the private key
Platform public key (`publicKey`)	Verify responses and async notifications	Obtain from the admin panel (App Configuration)

Languages & Repositories

Language	Package Coordinate	Requirements	Repository
Go	`github.com/opendaxpay/dax-pay-sdk-go`	Go ≥ 1.21, zero third-party dependencies	Gitee / GitHub
Java	`cn.daxpay.open:daxpay-open-sdk`	Java ≥ 8 (depends on Hutool)	Gitee / GitHub
Node.js	`@daxpay/open-sdk`	Node ≥ 18 (ESM + TypeScript)	Gitee / GitHub
PHP	`daxpay/open-sdk`	PHP ≥ 7.4 (ext-json / openssl / mbstring)	Gitee / GitHub
Python	`daxpay-open-sdk`	Python ≥ 3.10 (depends on cryptography)	Gitee / GitHub

Source-based installation for now

None of the SDKs are published to public package registries (Maven Central / npm / PyPI / Packagist). Use the source-based installation shown in each tab below.

Quick Start

Install

bash

go get github.com/opendaxpay/dax-pay-sdk-go@main

import "github.com/opendaxpay/dax-pay-sdk-go/daxpay"

Initialize the Client

config := daxpay.Config{
    ServiceUrl: "https://your-domain.com", // platform gateway URL
    MchNo:      "M200000001",              // merchant number
    AppId:      "APP001",                  // app ID
    PrivateKey: merchantPrivateKeyPem,     // merchant private key (PEM text)
    PublicKey:  platformPublicKeyPem,      // platform public key (PEM text)
    Timeout:    30 * time.Second,
}
client := daxpay.NewClient(config)

Pay

result, err := client.Pay(context.Background(), &daxpay.PayParam{
    BizOrderNo: "PAY20260916001",
    Title:      "Test goods",
    Amount:     100, // amount in cents
    Method:     "wechat_qr",
    NotifyUrl:  "https://example.com/notify",
})
if err != nil {
    log.Fatal(err)
}
fmt.Println(result.OrderNo, result.PayBody)

Main fields of PayResult: orderNo (platform order number), tradeNo (trade number), status (order status), payBody (payment payload: QR link / invoke params / redirect URL), payBodyType (code_url / pay_info / redirect_url).

Verify Callback

// rawBody is the raw HTTP request body of the async notification
ok := client.VerifyNotice(rawBody)

Generic Request (execute)

The convenience method currently covers payment only. Refund, refund sync, order query, close and all other endpoints can be called through each SDK's generic execute(path, param): path is the endpoint path (e.g. /unipay/refund), param holds the business fields (common fields such as mchNo/appId/sign/reqTime and the signature are filled in automatically by the SDK). See the API docs for field details.

result, err := client.Execute(ctx, "/unipay/refund", map[string]any{
    "bizOrderNo": "PAY20260916001",
    "amount":     100,
    "reason":     "customer refund",
})

Notes

Key format: every SDK accepts PEM text; for Python the private key is PKCS#8 and the public key is X.509 SPKI.
Always verify callbacks against the raw body: verifyNotice needs the original payload string. Parsing and re-serializing it changes field order/whitespace and breaks the signature.
Time and amount: the SDK generates reqTime (Beijing time, yyyy-MM-dd HH:mm:ss) per platform convention; amounts are in cents (Long).
Sandbox: just point serviceUrl at your test deployment — SDK behavior is environment-independent.

SDK Guide ​

Overview ​

Languages & Repositories ​

Quick Start ​

Install ​

Initialize the Client ​

Pay ​

Verify Callback ​

Generic Request (execute) ​

Notes ​