# Using RevenueCat Handle a deep link in your app and use the delegate methods to link web checkouts with RevenueCat in Flutter. After purchasing from a web paywall, the user will be redirected to your app by a deep link to redeem their purchase on device. Please follow our [Post-Checkout Redirecting](/docs/flutter/guides/web-checkout/post-checkout-redirecting) guide to handle this user experience. > **Note** If you're using Superwall to handle purchases, then you don't need to do anything here. > **Warning** You only need to use a `PurchaseController` if you want end-to-end control of the purchasing pipeline. The recommended way to use RevenueCat with Superwall is by putting it in observer mode. If you're using your own `PurchaseController`, you should follow our [Redeeming In-App](/docs/flutter/guides/web-checkout/linking-membership-to-iOS-app) guide. Using a PurchaseController with RevenueCat [#using-a-purchasecontroller-with-revenuecat] If you're using RevenueCat, you'll need to follow [steps 1 to 4 in their guide](https://www.revenuecat.com/docs/web/integrations/stripe) to set up Stripe with RevenueCat. Then, you'll need to associate the RevenueCat customer with the Stripe subscription IDs returned from redeeming the code. You can do this by extracting the ids from the `RedemptionResult` and sending them to RevenueCat's API by using the `didRedeemLink()` delegate method: > **Warning** This flow is for Stripe subscriptions. Stripe one-time purchases can return Stripe Checkout session IDs through the same legacy `stripeSubscriptionIds` field, but those IDs are not Stripe subscription IDs. Handle one-time purchases with Superwall entitlements or your own backend instead of sending those IDs to RevenueCat's Stripe subscription endpoint. ```dart import 'package:superwallkit_flutter/superwallkit_flutter.dart'; import 'package:purchases_flutter/purchases_flutter.dart'; import 'package:http/http.dart' as http; import 'dart:convert'; class MySuperwallDelegate extends SuperwallDelegate { // The user tapped on a deep link to redeem a code @override void willRedeemLink() { print('[!] willRedeemLink'); // Optionally show a loading indicator here } // Superwall received a redemption result and validated the purchase with Stripe. @override void didRedeemLink(RedemptionResult result) async { print('[!] didRedeemLink: $result'); // Send Stripe IDs to RevenueCat to link purchases to the customer if (result is! RedemptionResultSuccess) { return; } final storeIdentifiers = result.redemptionInfo.purchaserInfo.storeIdentifiers; if (storeIdentifiers is! StripeStoreIdentifiers) { return; } // Get a list of Stripe subscription ids tied to the customer final stripeSubscriptionIds = storeIdentifiers.subscriptionIds; if (stripeSubscriptionIds.isEmpty) { return; } const revenueCatStripePublicAPIKey = 'strp.....'; // replace with your RevenueCat Stripe Public API Key final appUserId = await Purchases.appUserID; // In the background, send requests to RevenueCat for (final stripeSubscriptionId in stripeSubscriptionIds) { try { final url = Uri.parse('https://api.revenuecat.com/v1/receipts'); final response = await http.post( url, headers: { 'Content-Type': 'application/json', 'Accept': 'application/json', 'X-Platform': 'stripe', 'Authorization': 'Bearer $revenueCatStripePublicAPIKey', }, body: jsonEncode({ 'app_user_id': appUserId, 'fetch_token': stripeSubscriptionId, }), ); if (response.statusCode != 200) { throw Exception( 'RevenueCat responded with ${response.statusCode}: ${response.body}', ); } final json = jsonDecode(response.body); print('[!] Success: linked $stripeSubscriptionId to user $appUserId: $json'); } catch (error) { print('[!] Error: unable to link $stripeSubscriptionId to user $appUserId: $error'); } } // After all network calls complete, invalidate the cache try { final customerInfo = await Purchases.getCustomerInfo(); /// If you're using Purchases.customerInfoStream, or keeping Superwall Entitlements in sync /// via RevenueCat's PurchasesDelegate methods, you don't need to do anything here. Those methods will be /// called automatically when this call fetches the most up to date customer info, ignoring any local caches. /// Otherwise, if you're manually calling Purchases.getCustomerInfo to keep Superwall's entitlements /// in sync, you should use the newly updated customer info here to do so. /// You could always access web entitlements here as well /// final webEntitlements = Superwall.shared.entitlements?.web; // Perform UI updates, like letting the user know their subscription was redeemed print('[!] Customer info updated after redemption'); } catch (error) { print('[!] Error fetching customer info: $error'); } } } ``` > **Note** The example throws when RevenueCat responds with an error so you can add retries, alerts, or custom UI. Adapt the error-handling strategy to your networking and logging requirements. Set up the delegate when configuring Superwall: ```dart void main() async { WidgetsFlutterBinding.ensureInitialized(); await Superwall.configure('pk_your_api_key'); // Set the delegate Superwall.shared.setDelegate(MySuperwallDelegate()); runApp(MyApp()); } ``` > **Warning** If you call `logIn` from RevenueCat's SDK, then you need to call the logic you've implemented inside `didRedeemLink()` again. For example, that means if `logIn` was invoked from RevenueCat, you'd either abstract out this logic above into a function to call again, or simply call this function directly. The web entitlements will be returned along with other existing entitlements in the `CustomerInfo` object accessible via RevenueCat's SDK. If you're logging in and out of RevenueCat, make sure to resend the Stripe subscription IDs to RevenueCat's endpoint after logging in. Alternative implementation using async/await properly [#alternative-implementation-using-asyncawait-properly] Here's a cleaner implementation that properly handles async operations: ```dart class MySuperwallDelegate extends SuperwallDelegate { @override void willRedeemLink() { print('[!] willRedeemLink'); // Show loading indicator } @override void didRedeemLink(RedemptionResult result) { // Don't use async here directly, spawn a separate task _handleRedemption(result); } Future _handleRedemption(RedemptionResult result) async { if (result is! RedemptionResultSuccess) { print('[!] Redemption did not succeed'); return; } final storeIdentifiers = result.redemptionInfo.purchaserInfo.storeIdentifiers; if (storeIdentifiers is! StripeStoreIdentifiers) { print('[!] Redemption did not come from Stripe'); return; } final stripeSubscriptionIds = storeIdentifiers.subscriptionIds; if (stripeSubscriptionIds.isEmpty) { print('[!] No Stripe subscription IDs found'); return; } const revenueCatStripePublicAPIKey = 'strp.....'; final appUserId = await Purchases.appUserID; // Link each subscription to RevenueCat await Future.wait( stripeSubscriptionIds.map((stripeSubscriptionId) async { try { await _linkSubscriptionToRevenueCat( stripeSubscriptionId, appUserId, revenueCatStripePublicAPIKey, ); } catch (e) { print('[!] Failed to link $stripeSubscriptionId: $e'); } }), ); // Refresh customer info try { await Purchases.getCustomerInfo(); print('[!] Successfully refreshed customer info'); } catch (e) { print('[!] Failed to refresh customer info: $e'); } } Future _linkSubscriptionToRevenueCat( String stripeSubscriptionId, String appUserId, String apiKey, ) async { final url = Uri.parse('https://api.revenuecat.com/v1/receipts'); final response = await http.post( url, headers: { 'Content-Type': 'application/json', 'Accept': 'application/json', 'X-Platform': 'stripe', 'Authorization': 'Bearer $apiKey', }, body: jsonEncode({ 'app_user_id': appUserId, 'fetch_token': stripeSubscriptionId, }), ); if (response.statusCode != 200) { throw Exception( 'RevenueCat responded with ${response.statusCode}: ${response.body}', ); } print('[!] Successfully linked $stripeSubscriptionId to $appUserId'); } } ``` Remember to add the `http` package to your `pubspec.yaml`: ```yaml dependencies: http: ^1.1.0 purchases_flutter: ^6.0.0 superwallkit_flutter: ^2.4.12 ```