Android Redirection SDK (Deprecated)

Paytm Redirection Android SDK is a secure and PCI-compliant way to accept Debit/Credit Card, Net-Banking, UPI and Paytm Wallet payments from your customers in your Android app. 

Note:

This SDK has been deprecated. For integrating our new SDK with advance features, please refer to this link.

1. When a customer clicks the Pay button, order related payload is passed to your server by the app.
2. This order payload is used to generate checksumhash by our server-side utility and merchant key on your server. Checksumhash is a signature used by Paytm to ensure that the request has not tampered. Utility to generate checksumhash is available here.
3. Your server passes the payload and checksumhash back to the app, which hands over these details to Paytm SDK.
4. SDK verifies payload and displays the Paytm payment checkout page.
5. Customer fills the payment details and completes the payment authentication. Once the payment is complete, a response is posted back to your app via callback.
6. Verify checksumhash received in response on your server-side. Utility to verify checksumhash is available here.
7. Verify the transaction status with Transaction Status API via server to server call. This protects you from scenarios where your account credentials are compromised or request/response has tampered.

Find the detailed interaction of each system component in the flowchart below:

Step 1: SDK Installation and Setup

Install SDK

Install Paytm Android SDK using the Android Studio and IntelliJ. To add SDK to your app, add the following dependency in your build.gradle:

dependencies {
	compile('com.paytm:pgplussdk:1.4.4') {
		transitive = true; 
	}
}

SMS Permission

To allow SDK to autoread the OTP sent by bank during account verification, you need the static and at runtime permissions. Add the following code to your AndroidManifest.xml to get static permission:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.READ_SMS"/>
<uses-permission android:name="android.permission.RECEIVE_SMS"/>

Use the code below to get the runtime permissions needed from user to auto-read the OTP:

if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED) {
	ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_SMS, Manifest.permission.RECEIVE_SMS}, 101);
}

Proguard Rules

If you're using proguard for your build, you need to add the following lines to your proguard file (proguard-rules.pro):

-keepclassmembers class com.paytm.pgsdk.paytmWebView$PaytmJavaScriptInterface {
   public *;
}

Step 2: Initialization

To initialize the Paytm SDK, use the following classes:

Object: Service

Service object is used to access PG services like initiating transaction, getting transaction callbacks, etc. This is different for staging and production and is created using the following snippet:

For Staging environment:

PaytmPGService Service = PaytmPGService.getStagingService();

For Production environment:

PaytmPGService Service = PaytmPGService.getProductionService();

Object: Order

Stores all the order related information which are required to be passed by you to Paytm. Order object is created by the following code snippets:

Map<String, String> paramMap = new HashMap<String,String>();
paramMap.put( "MID" , "rxazcv89315285244163");
// Key in your staging and production MID available in your dashboard
paramMap.put( "ORDER_ID" , "order1");
paramMap.put( "CUST_ID" , "cust123");
paramMap.put( "MOBILE_NO" , "7777777777");
paramMap.put( "EMAIL" , "username@emailprovider.com");
paramMap.put( "CHANNEL_ID" , "WAP");
paramMap.put( "TXN_AMOUNT" , "100.12");
paramMap.put( "WEBSITE" , "WEBSTAGING");
// This is the staging value. Production value is available in your dashboard
paramMap.put( "INDUSTRY_TYPE_ID" , "Retail");
// This is the staging value. Production value is available in your dashboard
paramMap.put( "CALLBACK_URL", "https://securestage.paytmpayments.com/theia/paytmCallback?ORDER_ID=order1");
paramMap.put( "CHECKSUMHASH" , "w2QDRMgp1234567JEAPCIOmNgQvsi+BhpqijfM9KvFfRiPmGSt3Ddzw+oTaGCLneJwxFFq5mqTMwJXdQE2EzK4px2xruDqKZjHupz9yXev4=")
PaytmOrder Order = new PaytmOrder(paramMap);

You can see the parameters used in the hashmap object along with their description in the table below:

Object: Certificate (optional)

Stores client-side SSL certificate related information and ensures secured handshake between your app and Paytm. Use the following code snippet to create a certificate object:

PaytmClientCertificate Certificate = new PaytmClientCertificate(String inPassword, String inFileName);
// inPassword is the password for client side certificate 
//inFileName is the file name of client side certificate

Note:

• Client certificate must be present in “raw” folder
• Pass filename without extension. For e.g: If filename is “clientCert.cert” then pass only “clientCert”

Step 3: Initiate Payment

Initialize Service

Parameters required to invoke initialize method are Order and Certificate objects:

Service.initialize(Order, Certificate);

In case you do not wish to pass the certificate, pass NULL:

Service.initialize(Order, null);

Call start transaction method using the service object:

Service.startPaymentTransaction(this, true, true, new PaytmPaymentTransactionCallback() {
	/*Call Backs*/
                       public void someUIErrorOccurred(String inErrorMessage) {}
                       public void onTransactionResponse(Bundle inResponse) {}
                       public void networkNotAvailable() {}
                       public void clientAuthenticationFailed(String inErrorMessage) {}
                       public void onErrorLoadingWebPage(int iniErrorCode, String inErrorMessage, String inFailingUrl) {}
                       public void onBackPressedCancelTransaction() {}
                       public void onTransactionCancel(String inErrorMessage, Bundle inResponse) {}
     });

The following parameters are used in the startPaymentTransaction in order:

• contextofyourActivity is the activity context in where this method is called
• A boolean variable (true/false) to hide or show the header bar.
• A boolean variable (true/false) to determine whether to send all checksum response parameters to PG server or not
• inPaymentTransactionCallback is a PaytmPaymentTransactionCallback instance to send callback messages back to your application. Details and description provided in next section.

Step 4: Handling callback from Paytm

You need to implement callback methods to handle payment response. This will provide the payment status and reason for transaction failures. Based on the reasons for failures, handling can be built at your end. Transaction callbacks can be listened via overriding methods of PaytmPaymentTransactionCallback.

Post completion of the transaction,

You will get a JSON response.

public void onTransactionResponse(Bundle inResponse) {
	/*Display the message as below */
	Toast.makeText(getApplicationContext(), "Payment Transaction response " + inResponse.toString(), Toast.LENGTH_LONG).show();
}

Note:

The completion of transaction does not imply that payment is successful. Payment could be unsuccessful or in failed state which needs to be derived from JSON.

User interface error:

When SDK is unable to load the payment page. This might happen in case SDK is not able to parse the transaction payload received from the app.

public void someUIErrorOccurred(String inErrorMessage) {
	/*Display the error message as below */
	Toast.makeText(getApplicationContext(), "UI Error " + inErrorMessage , Toast.LENGTH_LONG).show();
}

Network Error:

Due to weak or no internet connectivity on customer's device.

public void networkNotAvailable() {
	/*Display the message as below */
	Toast.makeText(getApplicationContext(), "Network connection error: Check your internet connectivity", Toast.LENGTH_LONG).show();
}

Client authentication failure:

This may happen due to multiple reasons:

1. Paytm services are not available due to a downtime
2. Server unable to generate checksum or checksum response is not in the proper format
3. Server failed to authenticate the client. That is the value of payt_STATUS is 2. // payt_STATUS hasn't been defined anywhere.

public void clientAuthenticationFailed(String inErrorMessage)  {
        /*Display the message as below */
        Toast.makeText(getApplicationContext(), "Authentication failed: Server error" + inResponse.toString(), Toast.LENGTH_LONG).show();
}

Error in loading web page:

When SDK is unable to load the payment page. This might happen due to server unavailability at Paytm's end or due to handshaking error with Paytm gateway.

public void onErrorLoadingWebPage(int iniErrorCode, String inErrorMessage, String inFailingUrl)  {
	/*Display the message as below */
	Toast.makeText(getApplicationContext(), "Unable to load webpage " + inResponse.toString(), Toast.LENGTH_LONG).show();
}

On press of Back button:

When a user presses the Back button on the payment page. Followed by pressing the Back button, there is a reconfirmation taken from the customer to leave the payment page.

public void onBackPressedCancelTransaction(){
	/*Display the message as below */
	Toast.makeText(getApplicationContext(), "Transaction cancelled" , Toast.LENGTH_LONG).show();
}

On transaction cancelled:

When a transaction gets cancelled. In case the user presses a Back or Cancel button and confirms to leave the page, the following callback is triggered.

dependencies {
	compile('com.paytm:pgplussdk:1.4.4') {
		transitive = true; 
	}
}

Step 5: Checksum Generation and Verification

• Generate Checksum

• Verification Checksum

You can find below the sample code for a language of your choice:

Post completion of integration on your staging environment, do a complete transaction from order summary page on your website or mobile app.

1. Attempt a test transaction using test paymodes credentials.
2. Ensure you re-verify transaction response with Transaction Status API via server to server call in payment flow and not separately as a one-time activity.
3. See the transaction details in the “Test Data” mode on your dashboard.

Once the test transaction is complete, move your code to live environment with production account details. Note that production accounts details are available after you have activated your account on the dashboard.

Lastly, it's recommended that you read about Managing Refunds and Late payment notifications.

In case of any issues with integration, please Get in touch.