Add in-app purchases and paywalls to your Flutter app with a single Dart package.
The Flutter SDK is on the roadmap and is not published yet. the cashsdk pub package does not
resolve from any registry today, so the code on this page describes the
intended API rather than a package you can install.
Shipping now? Use the iOS or Android SDK, which are available today. To be notified when this one lands, contact support@cashsdk.com.
The CashSDK Flutter SDK is one Dart package that runs on both iOS (StoreKit 2) and Android (Play Billing). Fetch offerings, run purchases, and read entitlements with the same async code on every target.
flutter pub add cashsdk
This adds the dependency to your pubspec.yaml:
dependencies:
cashsdk: ^1.0.0
Initialize CashSDK once in main(), before runApp. Use your publishable
key.
import 'package:flutter/material.dart';
import 'package:cashsdk/cashsdk.dart';
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await CashSDK.configure(publishableKey: 'csk_pk_…');
runApp(const MyApp());
}
Ship only publishable keys (csk_pk_… / csk_pk_…) in your app. Secret keys
(csk_sk_…) belong on your backend.
An offering holds the packages you present on a paywall, such as monthly and
annual.
final offering = await CashSDK.offerings();
final monthly = offering.monthly;
final annual = offering.annual;
Pass a package to purchase. CashSDK drives the native store flow, validates the
receipt, and returns the customer's updated entitlements.
final result = await CashSDK.purchase(offering.monthly);
if (result.entitlements['pro']?.isActive == true) {
unlockPro();
}
Read entitlements from any purchase or restore result to gate features.
if (result.entitlements['pro']?.isActive == true) {
// Show premium content
} else {
// Show the paywall
}
Let customers recover access on a new device or after a reinstall.
final result = await CashSDK.restorePurchases();
if (result.entitlements['pro']?.isActive == true) {
unlockPro();
}
Link the SDK to your own user ID so entitlements follow the customer across
devices and platforms. Call identify once the user has signed in.
CashSDK.identify('u_812');
Fetch the offering in initState, present its packages, and unlock on success.
import 'package:flutter/material.dart';
import 'package:cashsdk/cashsdk.dart';
class Paywall extends StatefulWidget {
const Paywall({super.key, required this.onUnlock});
final VoidCallback onUnlock;
@override
State<Paywall> createState() => _PaywallState();
}
class _PaywallState extends State<Paywall> {
Offering? _offering;
@override
void initState() {
super.initState();
CashSDK.offerings().then((o) => setState(() => _offering = o));
}
Future<void> _buy(Package package) async {
final result = await CashSDK.purchase(package);
if (result.entitlements['pro']?.isActive == true) widget.onUnlock();
}
@override
Widget build(BuildContext context) {
final offering = _offering;
if (offering == null) return const CircularProgressIndicator();
return Column(
children: [
const Text('Unlock Pro'),
FilledButton(
onPressed: () => _buy(offering.monthly),
child: Text(offering.monthly.localizedPrice),
),
TextButton(
onPressed: CashSDK.restorePurchases,
child: const Text('Restore purchases'),
),
],
);
}
}