Monetization: IAP, Subscriptions, Ads & RevenueCat

Real-world analogy

What is it?

Monetization in Flutter apps involves implementing in-app purchases, subscriptions, and advertising using platform-native billing systems abstracted by packages like in_app_purchase and RevenueCat, combined with ad SDKs like AdMob.

Real-world relevance

A field operations SaaS app uses RevenueCat to manage team subscriptions: free tier for 3 users, Pro at 29 USD/month for unlimited users. RevenueCat handles Apple/Google receipt validation, grace periods when a company's card expires, and sends webhooks to the NestJS backend to update the team's feature access in Supabase.

Key points

• In-app purchase types — Consumables (coins, credits — can be purchased repeatedly), Non-consumables (remove ads, unlock level — bought once), Auto-renewable subscriptions (monthly/annual — renews until cancelled), Non-renewing subscriptions (time-limited access, not auto-renewed). Each has different restoration logic.
• StoreKit (iOS) and Play Billing (Android) — iOS uses StoreKit 2 (modern Swift API, introduced iOS 15) and the legacy StoreKit 1. Android uses Google Play Billing Library 6+. Both have different product setup flows, testing environments (StoreKit Testing/TestFlight vs license testers), and receipt formats.
• in_app_purchase package — Flutter's official package:in_app_purchase abstracts StoreKit and Play Billing behind a common API. Handles: product listing, purchase initiation, purchase stream, delivery verification, and restore. Lower-level but cross-platform without a third-party dependency.
• RevenueCat integration — RevenueCat is a cross-platform subscription management SDK. It handles purchase validation, webhook delivery, entitlement management, and analytics. purchases_flutter is the Flutter SDK. Reduces 6 weeks of billing code to 2 days. Used by thousands of apps including major fintech products.
• Entitlements and offerings — RevenueCat models access as Entitlements (what the user can access: 'premium') mapped to Products (App Store/Play Store SKUs). Offerings are paywalls — different product bundles you can A/B test. Change products without app release by configuring in RevenueCat dashboard.
• Subscription lifecycle — Trial → Active → Grace period (payment failed, access continues briefly) → Lapsed (access revoked) → Cancelled → Expired. RevenueCat tracks all states via CustomerInfo. Your app checks entitlements, not raw subscription state, for cleaner logic.
• Receipt validation and server-side verification — Apple/Google receipts must be validated server-side to prevent fraud. RevenueCat handles this automatically. For custom backends: POST the receipt to Apple/Google validation servers, check the response, and update your DB. Never trust client-side receipt data alone.
• Paywall strategies — Hard paywalls (block feature entirely), soft paywalls (show feature, gate on use), freemium (core free, power features paid), trial-first (14-day trial before payment). RevenueCat Paywalls allows building no-code paywalls with remote configuration and A/B testing.
• AdMob integration — google_mobile_ads package provides Banner, Interstitial, Rewarded, and Native ads. Always initialize before using: MobileAds.instance.initialize(). Load ads before showing — preload rewarded ads especially. Comply with ATT (iOS) and consent requirements (GDPR) or ads won't show.
• ATT and consent frameworks — iOS 14+ requires App Tracking Transparency prompt before showing personalized ads. Use app_tracking_transparency package. Android requires UMP (User Messaging Platform) consent for GDPR. Failure to implement costs significant ad revenue in EU/US markets.
• Hybrid monetization — Many successful apps combine subscriptions + IAP + ads: free tier shows ads, paid subscription removes ads, consumable IAP for power users. Design your entitlement model to handle all three. RevenueCat's CustomerInfo.activeSubscriptions + activeEntitlements covers subscription state; ad visibility logic is separate.
• Pricing and conversion optimization — Offer annual plan prominently (typically 30-50% discount vs monthly — higher LTV). Trial conversion rates: 7-day trial converts better than 14-day in many categories. Price anchoring: show annual/monthly/weekly options to make monthly look reasonable. Test with RevenueCat Experiments.

Code example

// RevenueCat Flutter integration
import 'package:purchases_flutter/purchases_flutter.dart';

class PurchaseService {
  static Future<void> initialize() async {
    await Purchases.setLogLevel(LogLevel.debug);
    final config = PurchasesConfiguration(
      Platform.isIOS ? 'appl_your_key' : 'goog_your_key',
    );
    await Purchases.configure(config);
  }

  // Identify user after login (links purchases to your user ID)
  static Future<void> identifyUser(String userId) async {
    await Purchases.logIn(userId);
  }

  // Check if user has 'premium' entitlement
  static Future<bool> hasPremiumAccess() async {
    final customerInfo = await Purchases.getCustomerInfo();
    return customerInfo.entitlements.active.containsKey('premium');
  }

  // Fetch current offering and display paywall
  static Future<Offerings> getOfferings() async {
    return await Purchases.getOfferings();
  }

  // Purchase a package (e.g., monthly subscription)
  static Future<CustomerInfo> purchasePackage(Package package) async {
    try {
      return await Purchases.purchasePackage(package);
    } on PurchasesErrorCode catch (e) {
      if (e == PurchasesErrorCode.purchaseCancelledError) {
        throw const UserCancelledPurchaseException();
      }
      rethrow;
    }
  }

  // Restore purchases (required by App Store guidelines)
  static Future<CustomerInfo> restorePurchases() async {
    return await Purchases.restorePurchases();
  }
}

// Usage in paywall widget
class PaywallScreen extends StatefulWidget {
  const PaywallScreen({super.key});
  @override
  State<PaywallScreen> createState() => _PaywallScreenState();
}

class _PaywallScreenState extends State<PaywallScreen> {
  Offerings? _offerings;

  @override
  void initState() {
    super.initState();
    PurchaseService.getOfferings().then((o) => setState(() => _offerings = o));
  }

  @override
  Widget build(BuildContext context) {
    final offering = _offerings?.current;
    if (offering == null) return const CircularProgressIndicator();

    return Column(
      children: offering.availablePackages.map((pkg) {
        return ElevatedButton(
          onPressed: () async {
            final info = await PurchaseService.purchasePackage(pkg);
            if (info.entitlements.active.containsKey('premium')) {
              Navigator.pop(context, true);
            }
          },
          child: Text('${pkg.packageType.name} — ${pkg.storeProduct.priceString}'),
        );
      }).toList(),
    );
  }
}

Line-by-line walkthrough

1. 1. PurchasesConfiguration takes the platform-specific key — using Platform.isIOS ternary avoids shipping both keys to both platforms unnecessarily.
2. 2. Purchases.logIn(userId) must be called after your own auth completes — it links anonymous device purchases to your authenticated user, enabling cross-device subscription access.
3. 3. entitlements.active.containsKey('premium') is the canonical access check — always check entitlements, never raw subscription state, for clean feature gating logic.
4. 4. Purchases.getOfferings() fetches the current offering configured in RevenueCat dashboard — changing products requires no app update.
5. 5. offering.availablePackages contains the packages defined for that offering — monthly, annual, weekly, or custom configured in the dashboard.
6. 6. purchasePackage wraps the native StoreKit/Play Billing purchase flow — RevenueCat handles receipt posting and validation automatically.
7. 7. PurchasesErrorCode.purchaseCancelledError must be caught and handled gracefully — it's a normal user action, not an error to report.
8. 8. Purchases.restorePurchases() is required by App Store Review guidelines — failure to include it is a common rejection reason.

Spot the bug

class PremiumGate extends StatelessWidget {
  const PremiumGate({super.key, required this.child});
  final Widget child;

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: Purchases.getCustomerInfo(),
      builder: (context, snapshot) {
        final info = snapshot.data;
        final isPremium = info?.activeSubscriptions.isNotEmpty ?? false;
        if (!isPremium) return const PaywallScreen();
        return child;
      },
    );
  }
}

Explain like I'm 5

Fun fact

Hands-on challenge

More resources

• RevenueCat Flutter SDK documentation (RevenueCat Docs)
• purchases_flutter package (pub.dev)
• Flutter in_app_purchase package (pub.dev)
• Google Mobile Ads Flutter (pub.dev)
• Subscription lifecycle states explained (RevenueCat Blog)