Flutter SDK Integration

The steps to integrate the PhonePe Payment Gateway with flutter platform. We provide a plugin/bridge to integrate our SDK.

The minimum supported versions

  • Flutter Version: 2.17.0
  • Latest Flutter SDK Version: 2.0.1

We can implement with the below 2 steps:

  1. Add the native configuration (Android/iOS)
  2. Add the Plugin to the Flutter project
  1. Android – Add the native configuration in the Android Studio project
  2. iOS – Add the native configuration in the Xcode project
  3. Add the Plugin to your Flutter Project
    1. Init Method
    2. Start The PG transaction
    3. Helper Methods (For Android and iOS)
    4. Helper Methods (Only Android Specific)
      1. Get Package Signature for Android
      2. Get UPI Apps for Android
  4. Parameters
  5. Server Side Implementation
  6. Flutter Sample App

Android

Add the native configuration in the Android Studio project

  1. Add the below code to ‘repositories’ section of your project level build.gradle file
// Top-level build file where you can add configuration options common to all sub-projects/modules.

allprojects {
   repositories {
       google()
       maven {
            url  "https://phonepe.mycloudrepo.io/public/repositories/phonepe-intentsdk-android"
       }
   }
}

iOS

Add the native configuration in the Xcode project

1. In your Info.plist under the iOS Xcode project, create or append a new Array type node LSApplicationQueriesSchemes to append the following values:
<key>LSApplicationQueriesSchemes</key>
<array>
    <string>ppemerchantsdkv1</string>
    <string>ppemerchantsdkv2</string>
    <string>ppemerchantsdkv3</string>
    <string>paytmmp</string>
    <string>gpay</string>
</array>

For example, we have used: iOSIntentIntegration. (You can create your own identifier for your app)

URLScheme should match the below conditions

  • Only Alphabets (lower and upper case) and numbers are allowed.
  • We can allow special characters only like dot and Hyphen
  • The name should always start with alphabets.

The schema should be correct to redirect the app otherwise it will not redirect back to the merchant app.

Add the Plugin to your Flutter Project

  1. Add the dependency in the Flutter project from the command line
flutter pub add phonepe_payment_sdk
  1. Install the dependency from the command line
flutter pub get
  1. Import the package in your dart code
import 'package:phonepe_payment_sdk/phonepe_payment_sdk.dart';
  1. Call the PhonePe methods as below

Init Method

Initialize the init method before starting the transaction.

/**
   * This method is used to initiate PhonePe Payment sdk.
   * Provide all the information as requested by the method signature.
   * Params:
   *    - environment: This signified the environment required for the payment sdk
   *      possible values: SANDBOX, PRODUCTION
   *      if any unknown value is provided, PRODUCTION will be considered as default.
   *    - merchantId: The merchant id provided by PhonePe  at the time of onboarding.
   *    - appId: The appId provided by PhonePe at the time of onboarding.
   *    - enableLogging: If you want to enabled / visualize sdk log
   *        - enabled = YES
   *        - disable = NO
   */
static Future<bool> init(
    String environment,
    String appId,
    String merchantId,
    bool enableLogging) async
 
Example ->
	PhonePePaymentSdk.init(environmentValue, appId, merchantId, enableLogging)
        .then((val) => {
              setState(() {
                result = 'PhonePe SDK Initialized - $val';
              })
            })
        .catchError((error) {
      handleError(error);
      return <dynamic>{};
    });

To get App Id

  • Without calling PhonePePaymentSdk.init() method, getPackageSignatureForAndroid() method can’t be called to fetch the Signature as it will throw an error as the SDK is not initialized.Solution: Before calling the getPackageSignatureForAndroid() method, the merchant has to initialize the SDK using PhonePePaymentSdk.init(environmentValue, appId, merchantId, enableLogging). For initializing, merchant can pass the dummy value in the appId for the first time and later once the App ID is shared by the PhonePe Team, it should be replaced for the transactions to work smoothly.

Start The PG transaction

/**
   /*
    * This method is used to initiate PhonePe B2B PG Flow.
    * Provide all the information as requested by the method signature.
    * Params:
    * - body : The request body for the transaction as per the developer docs.
    * - appSchema: @Optional(for Android) Your custom app URL Schemes, as per the developer docs.
    * - checkSum: checksum for the particular transaction as per the developer docs.
    * - packageName: @Optional(for iOS) in case of android if intent url is expected for specific app.
    *
    * Return: Will be returning a dictionary / hashMap
    * {
    * status: String, // string value to provide the status of the transaction
    * // possible values: SUCCESS, FAILURE, INTERRUPTED
    * error: String // if any error occurs
    * }
    */
static Future<Map<dynamic, dynamic>?> startTransaction(String body,
    String appSchema, String checksum, String? packageName) async {
           var dict = 
          {
          'body': body,
          'callbackUrl': appSchema,
          'checksum': checksum,
          'packageName': packageName
          };
     Map<dynamic, dynamic>? result =
     await _channel.invokeMethod('startTransaction', dict);
     return result;
}

Example:

PhonePePaymentSdk.startTransaction(body, callback, checksum, packageName).then((response) => {
    setState(() {
                   if (response != null) 
                        {
                           String status = response['status'].toString();
                           String error = response['error'].toString();
                           if (status == 'SUCCESS') 
                           {
                             // "Flow Completed - Status: Success!";
                           } 
                           else {
                          // "Flow Completed - Status: $status and Error: $error";
                           }
                        } 
                   else {
                          // "Flow Incomplete";
                        }
                })
  }).catchError((error) {
  // handleError(error)
  return <dynamic>{};
  });

Helper Methods (For Android and iOS)

/**
   * This method is called to check the particular app is installed or not
   * Return: Bool
   */
 
static Future<bool> isPhonePeInstalled() // Check PhonePe App is installed in Phone
static Future<bool> isPaytmAppInstalled()  // Check Paytm App is installed in Phone 
static Future<bool> isGPayAppInstalled()  // Check GPay App is installed in Phone

Helper Methods (Only Android Specific)

Get Package Signature for Android
/**
   * This method is called to get package signature while creation of AppId in @Android only.
   * Return: String
   *  Non empty string -> app package signature
   *  NOTE :- In iOS, it will send null.
   */
static Future<String?> getPackageSignatureForAndroid()
Get UPI Apps for Android
 /**
   * This method is called to get list of upi apps in @Android only.
   * Return: String
   *  JSON String -> List of UPI App with packageName, applicationName & versionCode
   *  NOTE :- In iOS, it will throw os error at runtime.
   */ 
static Future<String?> getInstalledUpiAppsForAndroid()

Parameters

KeysData TypePossible Values
environmentString1. SANDBOX
2. PRODUCTION
merchantIdStringAdd the Merchant ID provided by the Integration Team
appIdStringAdd the PhonePe App Provided by the Integration Team.
Details to be shared with the integration team to generate the AppId:
iOS: Share the Apple Team ID
Android: Share the Android signature
enableLogsBoolShow the logs in the console in the SDK
1. true
2. false
bodyStringbase64String
appSchemaString[Only for iOS]Your App URL Scheme – To return the UI control back to the merchant app.
checksumStringChecksum for the particular transaction. Refer
apiEndPointStringThe API endpoint for the PG transaction. Refer
packageNameString[Only for Android]The Package name of the UPI app selected by the user.

Server Side Implementation

Step 1. Save the below-assigned value on your server
String apiEndPoint = "/pg/v1/pay";
Step 2. Construct the request body and encode it in Base 64 at your server as per the platform (Android/iOS):

For PG Pay API (Standard Checkout), refer to this Link.
For PG Pay API (Custom Checkout – UPI Open Intent), refer to this Link.
For PG Pay API (Custom Checkout – Other Instruments), refer to this Link.

Android
{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "transaction_123",
  "merchantUserId": "90223250",
  "amount": 1000,
  "mobileNumber": "9999999999",
  "callbackUrl": "https://webhook.site/callback-url",
  "paymentInstrument": {
    "type": "UPI_INTENT",
    "targetApp": "com.phonepe.app"
  },
  "deviceContext": {
    "deviceOS": "ANDROID"
  }
}

{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "MT7850590068188104",
  "merchantUserId": "MUID123",
  "amount": 10000,
  "callbackUrl": "https://webhook.site/callback-url",
  "mobileNumber": "9999999999",
  "paymentInstrument": {
    "type": "PAY_PAGE"
  }
}

Convert the JSON Payload to Base64 Encoded Payload

The above JSON request payload should be converted to the Base64 Encoded Payload and then the request should be sent in the below format.

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKICAibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogInRyYW5zYWN0aW9uXzEyMyIsCiAgIm1lcmNoYW50VXNlcklkIjogIjkwMjIzMjUwIiwKICAiYW1vdW50IjogMTAwMCwKICAibW9iaWxlTnVtYmVyIjogIjk5OTk5OTk5OTkiLAogICJjYWxsYmFja1VybCI6ICJodHRwczovL3dlYmhvb2suc2l0ZS9jYWxsYmFjay11cmwiLAogICJwYXltZW50SW5zdHJ1bWVudCI6IHsKICAgICJ0eXBlIjogIlVQSV9JTlRFTlQiLAogICAgInRhcmdldEFwcCI6ICJjb20ucGhvbmVwZS5hcHAiCiAgfSwKICAiZGV2aWNlQ29udGV4dCI6IHsKICAgICJkZXZpY2VPUyI6ICJBTkRST0lEIgogIH0KfQ=="
}

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKICAibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogIk1UNzg1MDU5MDA2ODE4ODEwNCIsCiAgIm1lcmNoYW50VXNlcklkIjogIk1VSUQxMjMiLAogICJhbW91bnQiOiAxMDAwMCwKICAicmVkaXJlY3RVcmwiOiAiaHR0cHM6Ly93ZWJob29rLnNpdGUvcmVkaXJlY3QtdXJsIiwKICAicmVkaXJlY3RNb2RlIjogIlJFRElSRUNUIiwKICAiY2FsbGJhY2tVcmwiOiAiaHR0cHM6Ly93ZWJob29rLnNpdGUvY2FsbGJhY2stdXJsIiwKICAibW9iaWxlTnVtYmVyIjogIjk5OTk5OTk5OTkiLAogICJwYXltZW50SW5zdHJ1bWVudCI6IHsKICAgICJ0eXBlIjogIlBBWV9QQUdFIgogIH0KfQ=="
}
iOS
{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "MT7850590068188104",
  "merchantUserId": "MU933037302229373",
  "amount": 10000,
  "callbackUrl": "https://webhook.site/callback-url",
  "mobileNumber": "9999999999",
  "deviceContext": {
    "deviceOS": "IOS"
  },
  "paymentInstrument": {
    "type": "UPI_INTENT",
    "targetApp": "PHONEPE"
  }
}

{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "MT7850590068188104",
  "merchantUserId": "MU933037302229373",
  "amount": 10000,
  "callbackUrl": "https://webhook.site/callback-url",
  "mobileNumber": "9999999999",
  "deviceContext": {
    "deviceOS": "IOS"
  },
  "paymentInstrument": {
    "type": "UPI_INTENT",
    "targetApp": "GPAY"
  }
}

{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "MT7850590068188104",
  "merchantUserId": "MU933037302229373",
  "amount": 10000,
  "callbackUrl": "https://webhook.site/callback-url",
  "mobileNumber": "9999999999",
  "deviceContext": {
    "deviceOS": "IOS"
  },
  "paymentInstrument": {
    "type": "UPI_INTENT",
    "targetApp": "PAYTM"
  }
}

{
  "merchantId": "MERCHANTUAT",
  "merchantTransactionId": "MT7850590068188104",
  "merchantUserId": "MUID123",
  "amount": 10000,
  "redirectUrl": "https://webhook.site/redirect-url",
  "redirectMode": "REDIRECT",
  "callbackUrl": "https://webhook.site/callback-url",
  "mobileNumber": "9999999999",
  "paymentInstrument": {
    "type": "PAY_PAGE"
  }
}

Convert the JSON Payload to Base64 Encoded Payload

The above JSON request payload should be converted to the Base64 Encoded Payload and then the request should be sent in the below format.

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKIAkibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogIk1UNzg1MDU5MDA2ODE4ODEwNCIsCiAgIm1lcmNoYW50VXNlcklkIjogIk1VOTMzMDM3MzAyMjI5MzczIiwKICAiYW1vdW50IjogMTAwMDAsCiAgImNhbGxiYWNrVXJsIjogImh0dHBzOi8vd2ViaG9vay5zaXRlL2NhbGxiYWNrLXVybCIsCiAgIm1vYmlsZU51bWJlciI6ICI5OTk5OTk5OTk5IiwKICAiZGV2aWNlQ29udGV4dCI6IHsKICAgICJkZXZpY2VPUyI6ICJJT1MiCiAgfSwKICAicGF5bWVudEluc3RydW1lbnQiOiB7CiAgICAidHlwZSI6ICJVUElfSU5URU5UIiwKICAgICJ0YXJnZXRBcHAiOiAiUEhPTkVQRSIKICB9Cn0="
}

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKICAibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogIk1UNzg1MDU5MDA2ODE4ODEwNCIsCiAgIm1lcmNoYW50VXNlcklkIjogIk1VOTMzMDM3MzAyMjI5MzczIiwKICAiYW1vdW50IjogMTAwMDAsCiAgImNhbGxiYWNrVXJsIjogImh0dHBzOi8vd2ViaG9vay5zaXRlL2NhbGxiYWNrLXVybCIsCiAgIm1vYmlsZU51bWJlciI6ICI5OTk5OTk5OTk5IiwKICAiZGV2aWNlQ29udGV4dCI6IHsKICAgICJkZXZpY2VPUyI6ICJJT1MiCiAgfSwKICAicGF5bWVudEluc3RydW1lbnQiOiB7CiAgICAidHlwZSI6ICJVUElfSU5URU5UIiwKICAgICJ0YXJnZXRBcHAiOiAiR1BBWSIKICB9Cn0="
}

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKICAibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogIk1UNzg1MDU5MDA2ODE4ODEwNCIsCiAgIm1lcmNoYW50VXNlcklkIjogIk1VOTMzMDM3MzAyMjI5MzczIiwKICAiYW1vdW50IjogMTAwMDAsCiAgImNhbGxiYWNrVXJsIjogImh0dHBzOi8vd2ViaG9vay5zaXRlL2NhbGxiYWNrLXVybCIsCiAgIm1vYmlsZU51bWJlciI6ICI5OTk5OTk5OTk5IiwKICAiZGV2aWNlQ29udGV4dCI6IHsKICAgICJkZXZpY2VPUyI6ICJJT1MiCiAgfSwKICAicGF5bWVudEluc3RydW1lbnQiOiB7CiAgICAidHlwZSI6ICJVUElfSU5URU5UIiwKICAgICJ0YXJnZXRBcHAiOiAiUEFZVE0iCiAgfQp9"
}

{
  "request": "ewogICJtZXJjaGFudElkIjogIk1FUkNIQU5UVUFUIiwKICAibWVyY2hhbnRUcmFuc2FjdGlvbklkIjogIk1UNzg1MDU5MDA2ODE4ODEwNCIsCiAgIm1lcmNoYW50VXNlcklkIjogIk1VSUQxMjMiLAogICJhbW91bnQiOiAxMDAwMCwKICAicmVkaXJlY3RVcmwiOiAiaHR0cHM6Ly93ZWJob29rLnNpdGUvcmVkaXJlY3QtdXJsIiwKICAicmVkaXJlY3RNb2RlIjogIlJFRElSRUNUIiwKICAiY2FsbGJhY2tVcmwiOiAiaHR0cHM6Ly93ZWJob29rLnNpdGUvY2FsbGJhY2stdXJsIiwKICAibW9iaWxlTnVtYmVyIjogIjk5OTk5OTk5OTkiLAogICJwYXltZW50SW5zdHJ1bWVudCI6IHsKICAgICJ0eXBlIjogIlBBWV9QQUdFIgogIH0KfQ=="
}
Step 3. Checksum Calculation

Select one of the salts shared with you and note its index. Construct the X-verify at your server as follows:

String checksum = sha256(base64Body + apiEndPoint + salt) + ### + saltIndex;
Step 4. Check the payment status

Once the payment is completed, please call the Check Transaction Status API to validate the response received via the App. You can call the Check Transaction Status at regular intervals to fetch the response from the PhonePe server in case a response is not received in the application even after 10 minutes of initiating the application.

Step 5. Handling Payment Status

The payment status can be Successful, Failed, Pending or any of the codes. For Pending, you should retry until the status changes to Successful or Failed.

Flutter Sample App

Refer to the Sample App to test the Plugin and use in your Flutter platform – Link

Updated on Nov 08, 2023