Maui.RevenueCat.InAppBilling

A .NET MAUI wrapper library for RevenueCat in-app purchases. Provides a unified C# API that abstracts away the need for you to use platform-specific code from Android and iOS native bindings.

Features

• Unified API for iOS and Android in-app purchases
• Subscription and one-time purchase support
• User authentication (anonymous and identified users)
• Subscription status and entitlement checking
• Trial/intro discount eligibility
• Subscriber attributes management
• Stub implementations for Windows and MacCatalyst (for development convenience)

Installation

dotnet add package Kebechet.Maui.RevenueCat.InAppBilling

Quick Start

1. Register the service

In your MauiProgram.cs:

builder.Services.AddRevenueCatBilling();

2. Inject and initialize

In App.xaml.cs, inject IRevenueCatBilling and initialize in OnStart():

public partial class App : Application
{
    private readonly IRevenueCatBilling _revenueCat;

    public App(IRevenueCatBilling revenueCat)
    {
        InitializeComponent();
        _revenueCat = revenueCat;
    }

    protected override void OnStart()
    {
        var revenueCatApiKey = string.Empty;

#if __ANDROID__
        revenueCatApiKey = "<your-android-api-key>";
#elif __IOS__
        revenueCatApiKey = "<your-ios-api-key>";
#endif

        _revenueCat.Initialize(revenueCatApiKey);
        base.OnStart();
    }
}

Important: Initialize must be called in OnStart(), not in the constructor.

API Reference

Initialization & State

| Method | Description | |--------|-------------| | Initialize(string apiKey) | Initialize RevenueCat with your platform-specific API key | | IsInitialized() | Check if the SDK has been initialized | | IsAnonymous() | Check if current user is anonymous | | GetAppUserId() | Get the current user ID |

Offerings & Products

| Method | Description | |--------|-------------| | GetOfferings(bool forceRefresh = false) | Fetch available offerings and packages | | CheckTrialOrIntroDiscountEligibility(List<string> identifiers) | Check eligibility for trials/intro pricing |

Purchases

| Method | Description | |--------|-------------| | PurchaseProduct(PackageDto package) | Initiate a purchase flow | | GetActiveSubscriptions() | Get list of active subscription identifiers | | GetAllPurchasedIdentifiers() | Get all purchased product identifiers | | GetPurchaseDateForProductIdentifier(string productSku) | Get purchase date for a specific product | | RestoreTransactions() | Restore previous purchases |

User Management

| Method | Description | |--------|-------------| | Login(string appUserId) | Log in an identified user | | Logout() | Log out and create anonymous user | | GetCustomerInfo() | Get current customer info and entitlements | | GetManagementSubscriptionUrl() | Get URL for subscription management |

Subscriber Attributes

| Method | Description | |--------|-------------| | SetEmail(string email) | Set user's email | | SetDisplayName(string name) | Set user's display name | | SetPhoneNumber(string phone) | Set user's phone number | | SetAttributes(IDictionary<string, string> attributes) | Set custom attributes |

Example: Complete Purchase Flow

public class PurchaseService
{
    private readonly IRevenueCatBilling _revenueCat;

    public PurchaseService(IRevenueCatBilling revenueCat)
    {
        _revenueCat = revenueCat;
    }

    public async Task<bool> PurchaseSubscription()
    {
        var offerings = await _revenueCat.GetOfferings();
        if (offerings.Count == 0)
            return false;

        var defaultOffering = offerings.FirstOrDefault(o => o.IsCurrent);
        var monthlyPackage = defaultOffering?.AvailablePackages
            .FirstOrDefault(p => p.Identifier == "monthly");

        if (monthlyPackage == null)
            return false;

        var result = await _revenueCat.PurchaseProduct(monthlyPackage);

        if (result.IsSuccess)
        {
            // Purchase successful
            return true;
        }

        if (result.ErrorStatus == PurchaseErrorStatus.PurchaseCancelledError)
        {
            // User cancelled - not an error
            return false;
        }

        // Handle other errors
        Console.WriteLine($"Purchase failed: {result.ErrorStatus}");
        return false;
    }

    public async Task<bool> HasActiveSubscription(string entitlementId)
    {
        var customerInfo = await _revenueCat.GetCustomerInfo();
        return customerInfo?.ActiveSubscriptions
            .Any(e => e == entitlementId) ?? false;
    }
}

Platform Support

| Platform | Support | |----------|---------| | Android | Full implementation | | iOS | Full implementation | | Windows | Stub (returns defaults) | | MacCatalyst | Stub (returns defaults) |

Stub implementations return:

• true for boolean methods
• Empty collections for list methods
• string.Empty for string methods
• null for nullable types

This allows you to build and test on Windows/Mac without platform conditionals.

Error Handling

The library follows a non-throwing approach for runtime errors:

• Exceptions are thrown only for developer mistakes (e.g., calling methods before Initialize())
• Runtime errors (network issues, store problems, etc.) return:
  • ErrorStatus in result DTOs (e.g., PurchaseResultDto.ErrorStatus)
  • Empty collections for list returns
  • null for nullable types

This design ensures your app never crashes due to store-related issues.

Common Error Codes

| Error | Description | |-------|-------------| | PurchaseCancelledError | User cancelled the purchase | | StoreProblemError | Issue with the app store | | NetworkError | Network connectivity issue | | ProductAlreadyPurchasedError | Product was already purchased | | PaymentPendingError | Payment is pending (e.g., awaiting approval) |

See PurchaseErrorStatus for the complete list.

Credits

• Native bindings for Android and iOS inspired by thisisthekap's Xamarin bindings
• Abstraction layer based on RevenueCatXamarin by BillFulton

Contributing

Feel free to create an issue or pull request. For major changes, please open an issue first to discuss your proposal - large PRs without prior discussion may be rejected.

License

This project is licensed under the MIT License.