> For the complete documentation index, see [llms.txt](https://docs.mychips.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mychips.io/flutter/reward-user.md).

# Reward User

#### 1. Fully Managed by MyChips

{% hint style="info" %}
Use this method only if you have selected Self-Managed Currency. If you already support S2S postback please skip this snippet.
{% endhint %}

To check for a reward use the checkReward function. It requires your adUnitId, a reward callback (which will be called if the checks shows that there is a reward), and an on error callback.

```dart
MCOfferwallSdk.instance.checkReward(
    adUnitId: "YOUR_AD_UNIT_ID",
    onReward: (reward) {
        //do something with the reward, here we just print it out
        //Be cautious: reward.virtualCurrencyReward returns a Double value.
        print("Reward: ${reward.virtualCurrencyReward}");
    },
    onError: (e, st) {
        //do something on error, here we just print it out
        print("Error: $e");
        print("Stacktrace: $st");
    });
```

> If there is no reward and no error, nothing will happen

You should check for the reward whenever the app is started or resumed. Example integration:

```dart
void main() {
  runApp(const MainApp());
}

class MainApp extends StatefulWidget {
  const MainApp({super.key});

  @override
  State<MainApp> createState() => _MainAppState();
}

class _MainAppState extends State<MainApp> {
  late final AppLifecycleListener _appLifecycleListener;

  @override
  void initState() {
    super.initState();
    initialize();
  }

  @override
  void dispose() {
    _appLifecycleListener.dispose();
    super.dispose();
  }

  Future<void> checkReward() async {
    MCOfferwallSdk.instance.checkReward(
      adUnitId: "YOUR_AD_UNIT_ID",
      onReward: (reward) {
        log("Reward: ${reward.virtualCurrencyReward}");
      },
      onError: (e, st) {
        log("Error: $e StackTrace: $st");
      },
    );
  }

  Future<void> initialize() async {
    //initialize the sdk and set the user id
    await MCOfferwallSdk.instance.init("YOUR_API_KEY");
    await MCOfferwallSdk.instance.setUserId("YOUR_USER_ID");

    //check for reward when the app is initialized
    checkReward();

    //check for reward when the app is resumed
    _appLifecycleListener = AppLifecycleListener(
      onResume: () {
        checkReward();
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return ...//your app body
  }
}

```

#### 2. Server-to-Server (S2S) Postbacks

If you prefer server-to-server communication, MyChips can send a postback to your server with bonus information. The configuration for postbacks is available in your publisher dashboard. This method is useful for validating and securely rewarding users without client-side manipulation.&#x20;

If you are testing in Sandbox mode, the value of the macro {user\_payout} will be 0.


---

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