> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pesaswap.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Flutter with Node Backend

Integrate Hyper SDK to your Flutter App using Pesaswap-node

<Info> Use this guide to integrate the `hyper` SDK to your Flutter app.</Info>

**Before following these steps, please configure your payment methods.**

## Requirements

* Android 5.0 (API level 21) and above
* Android Gradle Plugin 8.5+
* Gradle 8.8+
* AndroidX
* iOS 13.0 and above
* CocoaPods
* npm

## Installation

```bash theme={"system"}
$ npm install @Pesaswap-/Pesaswap-node
```

## 1. Setup the server

Follow the Server Setup section.

## 2. Build checkout page on the client

### 2.1 Install the `flutter_Pesaswap` library

Add `flutter_Pesaswap` to your `pubspec.yaml` file:

```yaml theme={"system"}
dependencies:
  flutter_Pesaswap: ^version_number
```

Run the following command to fetch and install the dependencies:

```bash theme={"system"}
flutter pub get
```

<Info>
  To apply plugins using Flutter, run the following command:

  ```bash theme={"system"}
  dart run flutter_Pesaswap:apply_plugins
  ```

  This command configures the necessary Flutter plugins for your project using the `flutter_Pesaswap` package. Ensure you have the package installed and configured correctly in your project. If you encounter any issues, check the package documentation for more details.
</Info>

## 3. Complete the checkout on the client

### 3.1 Initialize the Pesaswap SDK

Initialize `Hyper` onto your app with your publishable key using the `Hyper` constructor. To get a PublishableKey, please find it here.

```dart theme={"system"}
import 'package:flutter_Pesaswap/flutter_Pesaswap.dart';

final _hyper = FlutterPesaswap();
_hyper.init(HyperConfig(
  publishableKey: 'YOUR_PUBLISHABLE_KEY', 
  customBackendUrl: 'YOUR_CUSTOM_BACKEND_URL'
));
```

<Info>When utilizing a custom backend or logging system, you can add the `customBackendUrl` to `HyperConfig`.</Info>

### 3.2 Create a Payment Intent

Make a network request to the backend endpoint you created in the previous step. The `clientSecret` returned by your endpoint is used to complete the payment.

```dart theme={"system"}
Future<String> fetchPaymentParams() async {
  try {
    var response = await http.get(Uri.parse("$API_URL/create-payment"));
    return jsonDecode(response.body)["clientSecret"];
  } catch (error) {
    throw Exception("Create Payment API call failed");
  }
}
```

### 3.3 Initialize your Payment Session

Initialize a Payment Session by passing the `clientSecret` to the `initPaymentSession`:

```dart theme={"system"}
final params = PaymentMethodParams(clientSecret: 'YOUR_PAYMENT_INTENT_CLIENT_SECRET');
Session? _sessionId = await _hyper.initPaymentSession(params);
```

### 3.4 Present payment sheet and handle response

To display the Payment Sheet, integrate a "**Pay Now**" button within the checkout page, which, when clicked, invokes the `presentPaymentSheet()` method and handles the payment response.

Consider the below function, which invokes `presentPaymentSheet` and handles payment results:

```dart theme={"system"}
Future<void> _presentPaymentSheet() async {
  final presentPaymentSheetResponse = await _hyper.presentPaymentSheet(_sessionId!);
  if (presentPaymentSheetResponse != null) {
    final message = presentPaymentSheetResponse.message;
    setState(() {
      if (message.isLeft) {
        _statusText = "${presentPaymentSheetResponse.status.name}\n${message.left!.name}";
      } else {
        _statusText = "${presentPaymentSheetResponse.status.name}\n${message.right}";
      }
    });
  }
}
```

## Congratulations!

Now that you have integrated the Flutter SDK, you can **customize** the payment sheet to blend with the rest of your app.

<Warning>Please retrieve the payment status from the Pesaswap backend to get the terminal status of the payment. Do not rely solely on the status returned by the SDK, as it may not always reflect the final state of the transaction.</Warning>