APP Payment

This feature is suitable for merchants who wish to integrate third-party mobile payment wallets (such as WeChat Pay, Alipay, UnionPay QuickPass, etc.) within their mobile applications.

Integration Overview

The merchant's app invokes the SDK provided by a third-party mobile payment wallet to call its payment module. The merchant's app will redirect to the third-party mobile payment wallet app to complete the payment, and after payment, it redirects back to the merchant's app to display the payment result.

Currently supported mobile operating systems include: iOS (Apple) and Android.

PayCloud supports integrating WeChat Pay and Alipay+ (not just mainland China’s Alipay, but also AlipayHK, Gcash, KakaoPay, TNG, etc.) for in-app payments.

After the user completes the payment, merchants can receive payment notifications from PayCloud and can also proactively call the order query interface to obtain payment results. After receiving the payment result, PayCloud will synchronize and update the order information to the merchant to complete the remaining goods and services.

Important Notes

Ensure that online payment permissions are enabled when invoking this interface.

Interaction Details

Step 1: The user enters the merchant's app, selects items to purchase, confirms the purchase, and proceeds to the payment process. The merchant's backend service requests our app payment API to generate a payment order and transfers data to the app side.

Step 2: After the user clicks to initiate the payment operation, they enter the third-party mobile payment wallet app interface, where the payment is initiated, showing a confirmation payment page.

Step 3: The user confirms the payee and amount, clicks "Pay Now," which leads to a password input screen, allowing options like balance or bank card payment.

Step 4: After entering the correct password, the payment is completed, and the user's app displays a payment details page.

Step 5: It returns to the merchant's app, where the merchant's app customizes and displays the order processing result based on the payment outcome.

Development Guidelines

API List

We provide a set of REST APIs; please refer to the table below. These APIs offer SDKs in several programming languages; visit SDK Section for more details.

API Name	Description
App Pay Order	Submit a payment order through this API
Cancel Order	Close unpaid orders through this api and refund the user if payment has already occurred
Submit a refund request	If you submit a refund request through this API and the refund does not arrive immediately, you can call the refund inquiry API to get the progress of the refund.
Query order	Query the transaction result (consumption/pre-authorization/pre-authorization completion) of a positive transaction order through this API
Query refund	Query the transaction results of negative transaction orders (consumption cancellation/pre-authorization cancellation/consumption refund/pre-authorization completion refund) through this API
Transaction result notification	After the transaction, notify the merchant through this webhook to tell the merchant the result of the transaction

Instructions for Using the WeChat SDK

WeChat Pay officially provides guidance on how to invoke payment controls through Android and iOS client SDKs, including sample code. Please refer to the Development Guide and Invoke Payment in App.

For the 【Unified Order】API mentioned in the WeChat documentation, use PayCloud’s Place an Order via App Payment API. As an official service provider for WeChat Pay in Japan, we have integrated WeChat Pay functionality, simplifying the integration process. You only need to get the order parameters through our API and then invoke WeChat Pay.

The pay_params returned by the PayCloud app payment API is a JSON object with the following structure:

{
    "appid":"wx8888888888888888",
    "partnerid":"1900000109",
    "prepayid":"WX1217752501201407033233368018",
    "package":"Sign=WXPay",
    "noncestr":"5K8264ILTKCH16CQ2502SI8ZNMTM67VS",
    "timestamp":"5K8264ILTKCH16CQ2502SI8ZNMTM67VS",
    "sign":"5K8264ILTKCH16CQ2502SI8ZNMTM67VS"
}

Initiating Payment via Alipay+

Alipay+ is a gateway product that aggregates the payment functionalities of dozens of mobile payment wallets, enabling merchants to integrate multiple wallet features with a single development effort. This service is continuously expanding, allowing Japanese merchants to accept payments from all over the world using familiar payment methods.

To make it easier for developers, Alipay+ provides an intermediary H5 webpage that automatically detects installed apps on the user's phone, selects a supported app, and automatically redirects the payment request to that app, eliminating the need for merchants to integrate various wallet SDKs in different ways.

The pay_params returned by the PayCloud app payment API is a JSON object with the following structure:

{
    "paymentUrl": "https://open-sea.alipayplus.com/api/open/v1/ac/cashier/self/codevalue/checkout.htm?codeValue=281666040098XYLX6JEL8817jb48uYF304Ww"
}

paymentUrl is the cashier URL of Alipay+. You only need to display this web page within your app. Below are examples demonstrating how to display a web page within an app on Android and iOS.`

Android

// WebView is a component provided by Android that allows you to load and display web content within your application. You can embed a WebView in your app by following these steps.
<WebView
    android:id="@+id/webview"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

// Load the URL in an Activity or Fragment.
WebView webView = findViewById(R.id.webview);
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true); // 如果网页需要启用 JavaScript
webView.loadUrl("https://example.com");

IOS

// In iOS, WKWebView is typically used to load web pages within the application.
import WebKit

class ViewController: UIViewController {
var webView: WKWebView!
override func viewDidLoad() {
super.viewDidLoad()
webView = WKWebView(frame: self.view.frame)
self.view.addSubview(webView)
if let url = URL(string: "https://example.com") {
let request = URLRequest(url: url)
webView.load(request)
}
}
}

How does the Alipay+ app return to the merchant's app?

When placing an order with PayCloud, you can pass a return_url to us. This URL is a custom URL Scheme registered by the merchant's app (e.g., mymerchantapp://payment/success?order_id=123456789). After the payment is completed, the Alipay+ app can launch the merchant's app via this Scheme.

Alipay Offline Mobile Web Payment Implementation for APP Payments

For merchants who have not applied for online Alipay payment services, they can first jump from the merchant's APP to the Alipay APP and then access the offline mobile web payment interface to trigger the Alipay payment widget and complete the payment.

Key steps to implement the transition from offline to online payment:

• Jump from the merchant's APP to the Alipay APP. After opening your webpage in the Alipay APP, follow the method outlined in the Alipay official documentation: Triggering Alipay APP through alipays protocol for mobile website payments.
• After jumping to the Alipay APP, use your backend server to access PayCloud's offline mobile web payment interface. We will return the corresponding Alipay cash register HTTPS URL, and you just need to open this URL to trigger the payment widget.
• Please make sure to call the PayCloud interface in the Alipay APP; otherwise, it will be recognized as online payment and cannot trigger the payment.

Important Notes

Although this method can extend offline business to online scenarios, there are certain risks. Banks and acquirers may determine this action as non-compliant. Please use with caution to avoid potential restrictions or penalties.