Getting Started

GitHub
Downloads
Server

Frameworks

.NET MAUI

Operating Systems

Android

iOS

Shiny.Mobile.Pay is cross-platform in-app purchases for .NET MAUI — consumables, non-consumables and auto-renewable subscriptions — built on the current generation of each store’s API: StoreKit 2 on iOS and Google Play Billing Library 9 on Android. The companion Shiny.Mobile.Pay.Server package is the other half: an ASP.NET Core backend that verifies purchases and receives the stores’ server-to-server notifications (renewals, refunds, cancellations, billing problems).

In-app purchases, not card payments

This library sells digital goods through the App Store and Google Play. Apple Pay and Google Pay card payments for physical goods are a different thing — those are charged and reported by a payment processor such as Stripe, not by Apple or Google.

Features

• One IInAppPurchaseManager for StoreKit 2 and Google Play Billing 9
• Consumables, non-consumables and auto-renewable subscriptions — including Google base plans, offers and free trials, and Apple introductory offers
• Pending purchases handled properly — Ask to Buy on iOS, slow payment methods on Android
• Out-of-band updates (approvals, renewals, refunds, purchases on another device) via IPurchaseDelegate, listening from app launch
• AccountToken ties every purchase to your user — it comes back in App Store and Google Play server notifications
• Every purchase carries VerificationData that the server package verifies directly — Apple’s signed JWS or Google’s purchase token
• Nothing finishes automatically, so an app crash between payment and granting can never lose a purchase
• Server: App Store Server Notifications V2 and Google Play Real-time Developer Notifications, normalized into one PurchaseEvent stream — see Server

Setup

Install Shiny.Mobile.Pay into your MAUI app, then register it:

builder
    .UseMauiApp<App>()
    .UseShiny();

builder.Services.AddInAppPurchases<MyPurchaseDelegate>();

Products must exist in App Store Connect and the Google Play Console, and the app’s bundle id / package name must match — see Store Setup.

Loading products

public class StoreViewModel(IInAppPurchaseManager purchases)
{
    public async Task Load()
    {
        if (!await purchases.CanMakePaymentsAsync())
            return; // store unavailable, or payments restricted by parental controls/MDM

        var products = await purchases.GetProductsAsync(["coins_100", "remove_ads", "premium_monthly"]);
        foreach (var product in products)
            Console.WriteLine($"{product.Title} - {product.DisplayPrice} ({product.Type})");
    }
}

Unknown product ids are left out of the result rather than throwing. DisplayPrice is already localized for the user’s storefront — show it as-is.

Purchasing

var result = await purchases.PurchaseAsync("remove_ads", new PurchaseOptions
{
    AccountToken = currentUser.Id // a Guid - returned in server notifications
});

switch (result.Status)
{
    case PurchaseResultStatus.Success:
        // 1. verify on your server  2. grant  3. finish
        await api.VerifyAndGrant(result.Purchase!.VerificationData);
        await purchases.FinishPurchaseAsync(result.Purchase!, consume: false);
        break;

    case PurchaseResultStatus.Pending:
        // Ask to Buy / slow payment - do NOT grant yet; IPurchaseDelegate is called when it resolves
        break;

    case PurchaseResultStatus.Cancelled:
        break;

    case PurchaseResultStatus.AlreadyOwned:
        // Google Play only - offer "Restore Purchases"
        break;
}

Genuine failures (network, product not found, billing unavailable, verification failure) throw PayException with an ErrorCode. Cancellation is not an exception.

Always finish purchases

PurchaseAsync never finishes a purchase for you. Call FinishPurchaseAsync once the entitlement is granted. Google Play automatically refunds purchases that are not acknowledged within three days, and unfinished Apple transactions are redelivered on every launch.

Consumables

Google Play has no concept of a consumable product — it depends on how the purchase is finished. Pass consume: true for anything the user can buy again (coins, credits, lives) and consume: false for permanent unlocks and subscriptions. On iOS both simply finish the transaction.

Subscriptions & offers

For subscriptions, StoreProduct.SubscriptionOffers lists what the user can buy:

• Google Play — one entry per base plan and per offer the user is eligible for. Pass the chosen OfferToken in PurchaseOptions.OfferToken; without one, the first base plan is purchased.
• Apple — the introductory offer (only when the user is eligible) and any promotional offers. The App Store applies an eligible introductory offer automatically.

Each offer has PricingPhases (for example a FreeTrial phase of P1W followed by a Recurring phase of P1M), with ISO 8601 billing periods.

To upgrade or downgrade on Google Play, pass PurchaseOptions.Replacement with the old product id and purchase token. On iOS, changes within a subscription group are handled by the App Store and Replacement is ignored.

Out-of-band updates

Many purchase changes don’t happen while you’re awaiting PurchaseAsync: a parent approves an Ask to Buy request, a pending cash payment clears, a subscription renews, a refund is issued, or the user buys on another device. Implement IPurchaseDelegate:

public class MyPurchaseDelegate(IInAppPurchaseManager purchases, MyApi api) : IPurchaseDelegate
{
    public async Task OnPurchaseUpdated(Purchase purchase)
    {
        switch (purchase.State)
        {
            case PurchaseState.Purchased when !purchase.IsFinished:
                await api.VerifyAndGrant(purchase.VerificationData);
                await purchases.FinishPurchaseAsync(purchase, consume: purchase.ProductId == "coins_100");
                break;

            case PurchaseState.Revoked:
                await api.Revoke(purchase.OriginalTransactionId);
                break;
        }
    }
}

The same purchase can arrive more than once, so key your handling on TransactionId. The PurchaseUpdated event carries the same updates for UI that’s currently on screen.

Your server is the source of truth

The device only sees part of the picture — Google doesn’t expose subscription expiry on the device at all, and refunds can happen while the app is never opened. Treat the delegate as a convenience and let server notifications drive entitlements.

Entitlements & restoring

// What the user owns right now: non-consumables + active subscriptions
var owned = await purchases.GetEntitlementsAsync();

// Completed but never finished - check at startup
var unfinished = await purchases.GetUnfinishedPurchasesAsync();

// "Restore Purchases" button - on iOS this can prompt for the Apple Account password,
// so only call it in response to the user
var restored = await purchases.RestorePurchasesAsync();

// Platform subscription management UI
await purchases.ShowManageSubscriptionsAsync();

The Purchase record

Property	Apple (StoreKit 2)	Google Play
TransactionId	transaction id (new on each renewal)	order id (purchase token while pending)
OriginalTransactionId	original transaction id	purchase token
VerificationData	signed JWS transaction	purchase token
AccountToken	appAccountToken	obfuscatedAccountId
ExpirationDate	subscription expiry	not available on device
IsFinished	transaction finished	acknowledged
Environment	Production / Sandbox / Xcode	Unknown (the server can tell)

Samples

• Sample MAUI App
• Sample Server

AI Coding Assistant

Claude CodeGitHub Copilot

Step 1 — Add the marketplace:

claude plugin marketplace add shinyorg/skills

Step 2 — Install the plugin:

claude plugin install shiny@shiny

One plugin installs all 36 Shiny skills. Your agent loads only the skill relevant to what you're building, so there's no cost to having them all available.

Step 1 — Add the marketplace:

copilot plugin marketplace add https://github.com/shinyorg/skills

Step 2 — Install the plugin:

copilot plugin install shiny@shiny

One plugin installs all 36 Shiny skills. Your agent loads only the skill relevant to what you're building, so there's no cost to having them all available.

View Skills Repository

Links

• GitHub Repository