Monetization

Monetization: Subscriptions & In-App Purchases

This skill covers payment integration for Flutter apps, from choosing a provider to implementing paywalls and managing entitlements.

Provider Decision

Quick decision:

• Selling subscriptions through App Store / Play Store → RevenueCat
• Selling digital products, licenses, or SaaS outside stores → Lemon Squeezy
• Both → RevenueCat for mobile + Lemon Squeezy for web/backend

RevenueCat Setup

Read references/revenuecat.md for complete implementation guide.

Architecture Overview

Flutter App
  └─ purchases_flutter SDK
      └─ RevenueCat Backend
          ├─ Apple StoreKit (iOS subscriptions)
          ├─ Google Play Billing (Android subscriptions)
          └─ Amazon Appstore (optional)

RevenueCat acts as a single source of truth for subscription state across platforms. It handles:

• Receipt validation
• Subscription status tracking
• Cross-platform purchase syncing
• Webhook delivery to your backend
• Analytics and churn metrics

Quick Start

1. Create RevenueCat account at app.revenuecat.com
2. Create project, add app (iOS + Android)
3. Configure store credentials:
   • iOS: App Store Connect Shared Secret + In-App Purchase Key
   • Android: Google Play service account JSON
4. Create Products in each store (App Store Connect + Google Play Console)
5. Create Entitlements in RevenueCat (e.g., "premium")
6. Create Offerings with Packages (monthly, annual, lifetime)
7. Integrate SDK in Flutter app

Essential Code

Initialize SDK (call once at app start):

import 'package:purchases_flutter/purchases_flutter.dart';

Future<void> initRevenueCat() async {
  await Purchases.setLogLevel(LogLevel.debug); // Remove in production
  final config = PurchasesConfiguration('your_revenuecat_api_key')
    ..appUserID = null; // Anonymous until user logs in
  await Purchases.configure(config);
}

Check subscription status:

Future<bool> isPremium() async {
  final customerInfo = await Purchases.getCustomerInfo();
  return customerInfo.entitlements.active.containsKey('premium');
}

Show paywall (using RevenueCat UI):

import 'package:purchases_ui_flutter/purchases_ui_flutter.dart';

Future<void> showPaywall() async {
  final result = await RevenueCatUI.presentPaywall(
    displayCloseButton: true,
  );
  if (result == PaywallResult.purchased) {
    // Grant access
  }
}

Purchase a package:

Future<void> purchase(Package package) async {
  try {
    final result = await Purchases.purchase(
      PurchaseParams.package(package),
    );
    if (result.customerInfo.entitlements.active.containsKey('premium')) {
      // Success
    }
  } on PlatformException catch (e) {
    final code = PurchasesErrorHelper.getErrorCode(e);
    if (code == PurchasesErrorCode.purchaseCancelledError) {
      // User cancelled, don't show error
    }
  }
}

Lemon Squeezy Integration

Read references/lemonsqueezy.md for API details.

Architecture Overview

Flutter App
  └─ WebView or deep link to checkout
      └─ Lemon Squeezy (handles payment + taxes)
          └─ Webhook to your backend
              └─ Backend updates user entitlements
                  └─ Flutter app checks entitlements

Lemon Squeezy is a merchant of record — they handle global tax compliance, invoicing, and payment processing. You receive payouts minus their fee.

When to Use Lemon Squeezy Over RevenueCat

• Selling access to APIs, web dashboards, or digital content
• Need global tax compliance without handling it yourself
• Want a checkout experience outside of App Store/Play Store
• Selling one-time purchases (not just subscriptions)
• Apple/Google's 30% commission is too high for your margins

Integration Pattern

Since there's no Flutter SDK, integrate via:

1. Checkout URL — open in WebView or external browser
2. Webhooks — receive payment events on your backend
3. License validation — verify purchase in your app via API

// Open Lemon Squeezy checkout
import 'package:url_launcher/url_launcher.dart';

Future<void> openCheckout(String productId) async {
  final url = 'https://your-store.lemonsqueezy.com/checkout/buy/$productId'
      '?checkout[custom][user_id]=user_123';
  await launchUrl(Uri.parse(url), mode: LaunchMode.externalApplication);
}

Pricing Strategy

Common Mobile Pricing Models

Pricing Best Practices for Stores

• Offer annual plans — higher LTV, lower churn. Typical discount: 15-30% vs monthly
• Free trial > freemium for subscription apps (Apple and Google both support trial periods natively)
• Price anchoring — show annual price first, monthly price looks expensive by comparison
• Localized pricing — adjust prices by market purchasing power
• Introductory offers — Apple and Google support discounted first periods

Store Commission

Entitlement Architecture

Design entitlements to be platform-agnostic and forward-compatible:

// Good: abstract entitlement
enum AppEntitlement { premium, proPlan, teamPlan }

// Bad: tied to specific product
enum AppEntitlement { monthlySubscription, annualSubscription }

A user with "premium" entitlement might have:

• Monthly subscription via Google Play
• Annual subscription via App Store
• Lifetime purchase via promotion
• Free access via team plan

RevenueCat maps all of these to the same entitlement. Your app only checks entitlements.active.containsKey('premium').