In-App Purchases API

Sell digital goods and subscriptions in your iOS WebView app with StoreKit-powered In-App Purchases.

Within some apps, you can buy additional content or services. These kinds of purchases are called "in-app purchases". They can be an attractive source of revenue for developers and are very convenient for customers as they use existing accounts and payment sources for settlement. WebViewGold allows triggering App Store In-App Purchases. Make sure to own an Extended License of WebViewGold if you plan to use this feature in an end product. Need to upgrade? Learn how to upgrade here.

Option 1 (Default): RevenueCat

Create your free RevenueCat account to get started. Pricing information is available on their website. Then set up RevenueCat by following their setup wizards and documentation (pricing details are available on their website). Afterwards, add your details to Config.swift. This approach also supports the 15% Service Fee Tier Program of the Google Play Store and Apple's Small Business Program. If you participate in these reduced-fee programs, inform RevenueCat via their Apple Small Business Program or Google 15% reduced service fee pages. This is how setup in Config.swift looks like:

static let revenueCatAPIKey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" //Your RevenueCat API Key (sign up via tinyurl.com/register-revenuecat first, then follow tinyurl.com/api-key-revenuecat how to find it)
static let revenueCatProjectID = "xxxxxxxxx" //Your RevenueCat Project ID (sign up via tinyurl.com/register-revenuecat first, then follow tinyurl.com/project-id-revenuecat how to find it)

Ensure your Bundle ID in Xcode & App Store Connect matches the project configured in RevenueCat. Trigger a purchase or subscription using:

revenuecat://purchase?external_id=user_123&product=sub_30_days

external_id = User identifier, e.g., your customer email or user ID. product = ID displayed on the RevenueCat console.

Option 2: Manual (Non-RevenueCat)

In the first step, insert the App Store Connect details of your In-App Purchase "Shared Secret" in Config.swift file. To find your "Shared Secret" in App Store Connect, you need to first log into your App Store Connect account. Then, go to the "Users and Access" section, and select the "Shared Secret" tab. Your generated "Shared Secret" will be listed, and you can copy/paste it to the relevant "IAPSharedSecret" field in Config.swift of WebViewGold.

We care about the success of our customers and are here to support them in any way we can: That’s why we want to mention the App Store Small Business Program and the Google Play Store 15% Service Fee Tier Program here. Under these programs, eligible developers can qualify for a reduced 15% commission down from the standard 30% commission. It only takes minutes to fill out their forms, and they can potentially save you 50% of fees (reduction from 30% commission to 15%). Once approved, you will receive the reduced commission rate for all paid apps and in-app purchases made by customers on the respective stores. Find more information on the Apple program here and on the Google Play program here.

After setup, for in-app purchase products just link to this kind of URL:

<a href="inapppurchase://?package=IN-APP_PURCHASE_PRODUCT_IDENTIFIER&disableadmob=true&successful_url=https://www.google.com">Buy In-App Purchase</a>

• The "package" is the product identifier of the item you want to sell.
• The "successful_url" is the URL you want the app to load once the purchase is complete.
  • You may want to save a cookie on this page so that your web app remembers that the purchase has been made.
• Include "disableadmob=true" if you would like to disable AdMob ads after the purchase of the product.

<a href="inappsubscription://?package=IN-APP_PURCHASE_PRODUCT_IDENTIFIER&expired_url=https://www.yahoo.com&successful_url=https://www.google.com">Start In-App Subscription</a>

• The "package" is the product identifier of the subscription you want to sell.
• The "successful_url" is the URL you want the app to load once the purchase is complete.
  • You may want to save a cookie on this page so that your web app remembers that the subscription has been activated.
• The "expired_url" is the URL you want the app to load when the subscription is no longer valid.
  • You may want to update/delete a cookie on this page so that your web app remembers that the subscription has been deactivated.

<script>
// Utility function to wait for a variable to be defined
function waitForVariable(variableName, callback, timeout = 5000) {
    const startTime = Date.now();

    (function checkVariable() {
        if (window[variableName] !== undefined) {
            callback(window[variableName]);
        } else if (Date.now() - startTime < timeout) {
            setTimeout(checkVariable, 100);
        } else {
            console.error(`Timeout: ${variableName} was not set within ${timeout} ms`);
        }
    })();
}

// Example: Handling In-App Purchase/Subscription variables
waitForVariable("planID", function(planID) {
    console.log("planID:", planID);
    // Send the Product ID to your server
    sendToServer("planID", planID);
});

waitForVariable("transactionIdentifier", function(transactionIdentifier) {
    console.log("transactionIdentifier:", transactionIdentifier);
    // Send the Transaction ID to your server
    sendToServer("transactionIdentifier", transactionIdentifier);
});

waitForVariable("subreceipts", function(subreceipts) {
    console.log("subreceipts:", subreceipts);
    // Send Subscription Receipt IDs to your server
    sendToServer("subreceipts", subreceipts);
});

// Function to send data to your server for validation
function sendToServer(key, value) {
    fetch("https://example.com/api/validate", {
        method: "POST",
        headers: {
            "Content-Type": "application/json"
        },
        body: JSON.stringify({ [key]: value })
    })
    .then(response => response.json())
    .then(data => console.log(`Server Response for ${key}:`, data))
    .catch(error => console.error(`Error sending ${key}:`, error));
}
</script>

Restore Purchases: A restoreinapppurchases:// call allows your app to re-enable previously purchased content. When a user taps a link with this URL scheme, the app initiates a process to revalidate and restore in-app purchases—ideal for scenarios like app reinstallation or device change. Simply add a link like the following to let users restore their purchases:

<a href="restoreinapppurchases://">Restore Purchases</a>

Cancel Subscription: A cancelinapppurchase:// call directs users to the official Apple subscription management portal, allowing them to cancel their subscriptions through Apple's native interface. Simply add a link like the following to forward users to manage their subscriptions:

<a href="cancelinapppurchase://">Cancel Subscription</a>

• If successful (example United States of America): var storeLocation = 'US';
• If no country code is found: var storeLocation = null;

Note: Using our API for delivering paid content to app users does carry some risk of technically savvy users accessing the content without paying for it. This could occur through various methods, such as retrieving and opening the Success URL link directly, canceling subscription products after uninstalling the app, or using withdrawal rights and chargeback processes for credit cards. However, it is crucial to note that some level of risk is present with any digital approach. While we continue to work on ways to reduce these risks, it is ultimately up to the WebViewGold user/developer to accept the risk of unauthorized/unpaid access to content when using the suggested approach, as the API comes without a warranty. Despite this, the benefits of using our API generally outweigh the risks for most users. To ensure accurate revenue reporting and identify potential discrepancies, we recommend tracking and comparing the sales data of App Store Connect with server-side activations of in-app purchase products.