Custom UI SDK Integration in React Native App

For merchants who have built their app on a react native platform - Paytm provides a plugin for you to conveniently integrate Custom UI SDK for both Android and iOS. In this document, we will highlight the steps required to integrate Custom UI SDK with a native plugin for your app. This plugin helps you to build a seamless and responsive checkout experience for your iOS or Android application.

Pre-requisites

Before you begin the integration, make sure you follow the steps below:

Create an account on Paytm as a merchant. Click how to create an account.

Note: Save the MID and merchant key generated in the above step.
The additional details such as Client Id and Client Secret Key will be shared with you over an email after the approval.
Go through the checksum logic to understand how to generate and validate the checksum.
Get the staging android or iOS Paytm app for integration testing on the merchant staging environment. For login into the staging Paytm app, use mobile no. 7777777770 and OTP 888888.

Staging Credentials

Integration steps for Paytm Custom UI SDK in React Native project

Add plugins to your react-native project.

npm install paytm-customuisdk-react-native --save
react-native link paytm-customuisdk-react-native

Open MainApplication.java class in an android directory of react native project.
```
import com.paytm.PaytmCustomuisdkPackage;
```

Then add new PaytmCustomuisdkPackage() to the list return in getPackages() method if not auto added after react-native link command in PackageList class.

@Override
       protected List<ReactPackage> getPackages() {
         @SuppressWarnings("UnnecessaryLocalVariable")
         List<ReactPackage> packages = new PackageList(this).getPackages();
         // Packages that cannot be autolinked yet can be added manually here, for example:
         packages.add(new PaytmCustomuisdkPackage());
         return packages;
       }

Append the following line to settings.gradle file.

include ':paytm-customuisdk-react-native'
project(':paytm-customuisdk-react-native').projectDir = new File(rootProject.projectDir, '../node_modules/paytm-customuisdk-react-native/android')

Add the following lines in the dependencies section of your app’s build.gradle file.
```
implementation project(':paytm-customuisdk-react-native');
```

Add below maven URL in repositories of project android/build.gradle.

allprojects {
   repositories {
       ...
       maven {
           url "https://artifactory.paytm.in/libs-release-local"
       }
   }
}

Enable multidex to use this sdk as given below in android/app/build.gradle.
```
android {
  ...
 defaultConfig {
   ...
   multiDexEnabled true
 }
}
dependencies {
   ...
  implementation 'com.android.support:multidex:1.0.3'
}
```
Note: To help you with the integration, we have provided a sample merchant app integrated with this SDK. To get the sample app, please click here.

Open Podfile and Update Platform Version.

Navigate to the ios folder and open Podfile. You can do this using the following code.
```
$ cd ios && open podfile.
```
Install Pods Using Cocoapods.

Install pods after updating the iOS platform: pod install && cd ..
Add the following in ios project.

Open the projectName.workspace in ios folder.
1. Open Info.plist : Add LSApplicationQueriesSchemes. Change its type to Array. Create a new item in it and set its value as "paytm".
2. Go to Info tab -> URL Types: Add a new URL Type that you’ll be using as the callback from Paytm App (URL Scheme: "paytm"+"MID"). Example: paytmMid123.
3. Open AppDelegate.m: Add following method before the end of the file ended by @end.
4. Open AppDelegate.m and import LinkingManager to the top of the file which has delegate methods for implementing and handling URLScheme(response from Paytm invoke will be received here in this method. Which in turns notifies the Plugin.).

#import <React/RCTLinkingManager.h>
 
- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url
            options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options
{
  
  NSString *urlString = url.absoluteString;
  NSDictionary *userInfo =
  [NSDictionary dictionaryWithObject:urlString forKey:@"appInvokeNotificationKey"];
  [[NSNotificationCenter defaultCenter] postNotificationName:
   @"appInvokeNotification" object:nil userInfo:userInfo];
  return [RCTLinkingManager application:app openURL:url options:options];
}

XCode configurations

In XCode, in the project navigator, right-click Libraries ➜ Add Files to [your project's name].
Go to node_modules ➜ paytm-customuisdk-react-native and add PaytmCustomuisdk.xcodeproj.
In XCode, in the project navigator, select your project. Add libRNPaytmCustomuiSdk.a to your project's Build Phases ➜ Link Binary With Libraries.
Run your project (Cmd+R).

Note: To help you with the integration, we have provided a sample merchant app integrated with this SDK. To get the sample app, please click here.

Methods available in React Native SDK

Now you can access SDK methods from ‘yourpageName’.js or .tsx file as below and Paytm consent checkbox view:

import PaytmCustomuisdk, { PaytmConsentCheckBox,} from 'paytm-customuisdk-react-native';
 
export default function HomePage{
 
fetchAuthCode() {
   PaytmCustomuisdk.fetchAuthCode(clientId, mid)
       .then((res) => {
         setResult(JSON.stringify(res));
         setAuthCode(res.response);
       })
       .catch((err) => {
         setResult(err.message);
       });
 }
 
return (
          <View style={{ padding: 8 }}>
             <View>
               <PaytmConsentCheckBox
                 onChange={(e: boolean) => setAuthCheck(e)}
               />
             </View>
             <TextInput
               style={styles.textInput}
               defaultValue={clientId}
               placeholder={'Client Id'}
               onChangeText={(e) => setClientId(e)}
             />
             <View style={{ margin: 16 }}>
               <Button title="Fetch" onPress={() => fetchAuthCode()} />
             </View>
           </View>
 );
}

Implement the following methods to extract Paytm user’s saved instruments.

isPaytmAppInstalled: This method is used to check whether Paytm is installed or not.

isPaytmAppInstalled

Method Usage:

PaytmCustomuisdk.isPaytmAppInstalled()

Response: Boolean

Parameter	Description
True	In case, Paytm App is installed and supports the feature to extract authcode
False	In case, Paytm App is not there or does not support the feature to extract authcode

fetchAuthCode: This method is called to fetch authcode which shows consent checkbox dialog and only return authcode by pressing the ok button of dialog when the user checked the shown consent checkbox if Paytm app is installed.

fetchAuthCode

Method Usage:

PaytmCustomuisdk.fetchAuthCode(clientId, mid)

Method Parameters:

Attribute

Description

Mandatory

clientId

String

Unique Id given by Paytm app.

Yes

mid

String

Unique Identifier given by Paytm app.

Yes

Response:

 {"response" : authCode}

Attribute

Description

authCode

String

Alphanumeric authCode string e.g. ‘Apfdf-2234-nhdjshj-wers’ in case auth code fetched

You need to call the OAuth token API using the authorization code received to receive the refresh token and SSO token associated with the Paytm user.
Note: SSO token will be used to fetch saved instruments of paytm user and refresh token will be used to get a new SSO token of paytm user after its expiry.

3
After the user adds the product in the cart and clicks the button to proceed for checkout, your app calls the backend server to get the order payout. Then, your backend server calls Initiate Transaction API from the backend to generate the Transaction Token.

Note: In case you wish to use the custom Callback URL in Initiate Transaction API then please include the config setMerchantCallbackUrl during Initialization of SDK.
4
Using the transaction token received above, your backend server calls the Fetch Payment Options API to receive the different payment options including the user's saved instruments and other instruments like CC/DC, NB, UPI, EMI etc.

Note: In case you do not want to create an order first, you may call the Fetch Payment Options API before Initiate Transaction. For more details please Get in touch with us.

Call initPaytmSDK method

You need to call initPaytmSDK method before calling any Transaction method. After calling the transaction method response will be in the “then” method in case of success and in “catch” method in case of error.

Note: After any transaction method. It is necessary to call the initPaytmSDK method again.

import PaytmCustomuisdk, { PaytmConsentCheckBox,} from 'paytm-customuisdk-react-native';

export default function HomePage{

initPaytmSdk() {
   PaytmCustomuisdk.initPaytmSDK(
     mid,
     orderId,
     txnToken,
     amount,
     isStaging,
     ''
   );
 }
 
goForWalletTransaction() {
  PaytmCustomuisdk.goForWalletTransaction(paymentFlow)
     .then((res) => {
       showAlert(JSON.stringify(res), true);
     })
     .catch((err) => {
       showAlert(err.message, false);
     });
   }
}

Response from Transaction method:

{
    "ORDERID": "PARCEL15816826759",
    "MID": "AliSub58582630351896",
    "TXNID": "20200214111212800110168052313701129",
    "TXNAMOUNT": "1.00",
    "PAYMENTMODE": "CC",
    "CURRENCY": "INR",
    "TXNDATE": "2020-02-14 17:48:13.0",
    "STATUS": "TXN_SUCCESS",
    "RESPCODE": "01",
    "RESPMSG": "Txn Success",
    "MERC_UNQ_REF": "test4",
    "UDF_1": "test1",
    "UDF_2": "test2",
    "UDF_3": "test3",
    "ADDITIONAL_INFO": "test5",
    "GATEWAYNAME": "ICICIPAY",
    "BANKTXNID": "68568621250",
    "BANKNAME": "HSBC",
    "PROMO_CAMP_ID": "PROMO CODE",
    "PROMO_RESPCODE": "702",
    "PROMO_STATUS": "FAILURE"
}

Method Usage:

PaytmCustomuisdk.initPaytmSDK(
     mid,
     orderId,
     txnToken,
     amount,
     isStaging,
     ''
   );

Method Parameters:

Parameter	Description	Mandatory
mid (string)	Merchant id identifying a merchant	Yes
orderId (string)	Unique identifier for current order	Yes
txnToken (string)	Transaction token to identify the current transaction received in response to Initiate Transaction API from Paytm	Yes
amount (string)	Order amount for the current transaction	Yes
isStaging (boolean)	To set the staging environment	Yes
callbackUrl (string)	Use this to define the custom CallbackUrl for receiving the result of the Transaction	No

6
Proceed for the transaction

When the user clicks on the Pay button after entering the payment instrument’s details in the selected payment method, you need to proceed for the transaction. Please follow the steps below for proceeding with the transaction.

Invoke the goForWalletTransaction method to call Process Transaction API for wallet transaction.

Method Usage:

PaytmCustomuisdk.goForWalletTransaction(paymentFlow)

Method Parameters:

Attribute

Description

Mandatory

paymentFlow

String

current payment flow (NONE, ADDANDPAY)

Yes

7
Integration of Additional/Optional Methods

openPaytmAppForAddMoneyToWallet: This method can be used to invoke and complete the transaction from Paytm App.

openPaytmAppForAddMoneyToWallet

Method Usage:

PaytmCustomuisdk.openPaytmAppForAddMoneyToWallet()

Sample Response:

{
  "ORDERID": "PARCEL16105282330",
  "MID": "AliSub585826303xx8xx",
  "TXNID": "202101131112128001101688774748xxxxxx",
  "TXNAMOUNT": "1.00",
  "PAYMENTMODE": "PPI",
  "CURRENCY": "INR",
  "TXNDATE": "2021-01-13 14:27:12.0",
  "STATUS": "TXN_SUCCESS",
  "RESPCODE": "01",
  "RESPMSG": "Txn Success",
  "MERC_UNQ_REF": "test4",
  "UDF_1": "test1",
  "UDF_2": "test2",
  "UDF_3": "test3",
  "ADDITIONAL_INFO": "test5",
  "GATEWAYNAME": "WALLET",
  "BANKTXNID": "151096542207",
  "BANKNAME": "WALLET"
}

getBin: Get Bin can be used to get the bin information and success rate of the entered card. It can be used with a Transaction token or Access token.

getBin

Note: Call this method after the initPaytmSDK method in case tokenType is TXN_TOKEN.

Method Usage:

PaytmCustomuisdk
     .getBin(this.cardNumber, tokenType, this.txnToken, this.mid, null)

Method Parameters:

Parameter	Description	Mandatory
cardSixDigit String	First six digits of the card	Yes
tokenType String	It can be "TXN_TOKEN","ACCESS"	Yes
token String	Token value used(access/txntoken)	Yes
mid String	Merchant ID	Yes
referenceID String	Unique ID between 10 to 20 digits and is only required in case of tokenType as ACCESS. It should be similar to the value used in access token generation.	If token type is ACCESS

Response:

{
    "head": {
        "requestId": "null",
        "responseTimestamp": "1630415256947",
        "version": "v1"
    },
    "body": {
        "authModes": ["otp"],
        "binDetail": {
            "bin": "541919",
            "binTokenization": "false",
            "channelCode": "MASTER",
            "channelName": "MASTER",
            "cnMax": "16",
            "cnMin": "16",
            "cvvL": "3",
            "cvvR": "true",
            "expR": "true",
            "isActive": "true",
            "isIndian": "true",
            "issuingBank": "HDFC Bank",
            "issuingBankCode": "HDFC",
            "paymentMode": "DEBIT_CARD"
        },
        "errorMessage": "EMI not available",
        "hasLowSuccessRate": {
            "msg": "",
            "status": "false"
        },
        "iconUrl": "https://staticgw3.paytmpayments.com/33.1.1/images/wap/merchantLow/master.png",
        "isEmiAvailable": false,
        "isHybridDisabled": false,
        "oneClickMaxAmount": "2000",
        "oneClickSupported": false,
        "prepaidCard": false,
        "prepaidCardMaxAmount": "100000",
        "resultInfo": {
            "resultCode": "0000",
            "resultMsg": "Success",
            "resultStatus": "S"
        }
    }
}

fetchNBList: FetchNBList can be used to get the list of all netbanking banks along with their success rate. This method can be used with a transaction or access token.

fetchNBList

Note: Call this method after the initPaytmSDK method in case tokenType is TXN_TOKEN.

Method Usage:

PaytmCustomuisdk
     .fetchNBList(tokenType, this.txnToken, this.mid, this.orderId, null)

Method Parameters:

Parameter	Description	Mandatory
orderID String	Unique identifier for current order	If tokenType is TXN_TOKEN
tokenType String	It can be "TXN_TOKEN","ACCESS"	Yes
token String	Token value used(access/txntoken)	Yes
mid String	Merchant ID	Yes
referenceID String	Unique ID between 10 to 20 digits and is only required in case of tokenType as ACCESS. It should be similar to the value used in access token generation.	If token type is ACCESS

Response:

{
    "head":{
        "requestId":null,
        "responseTimestamp":"1591622928848",
        "version":"v1"
    },
    "body":{
        "extraParamsMap":null,
        "resultInfo":{
            "resultStatus":"S",
            "resultCode":"0000",
            "resultMsg":"Success"
        },
        "nbPayOption":{
            "displayName":"Net Banking",
            "isDisabled":{
                "status":"false",
                "msg":""
            },
            "payChannelOptions":[
                {
                "isDisabled":{
                    "status":"false",
                    "msg":null
                },
                "hasLowSuccess":{
                    "status":"false",
                    "msg":""
                },
                "iconUrl":"AXIS.png",
                "isHybridDisabled":false,
                "channelCode":"AXIS",
                "channelName":"Axis Bank"
                },
                {
                "isDisabled":{
                    "status":"false",
                    "msg":null
                },
                "hasLowSuccess":{
                    "status":"false",
                    "msg":""
                },
                "iconUrl":"HDFC.png",
                "isHybridDisabled":false,
                "channelCode":"HDFC",
                "channelName":"HDFC Bank"
                }
            ]
        }
    }
}

Parameter	Description
channelName	Bank Name
channelCode	Bank Code
iconUrl	Bank Logo URL
hasLowSuccess	Information about bank’s success rate (HasLowSuccess contains Boolean status and String msg )

fetchEmiDetails (For Android Only): This method is used to fetch available EMI plans on a given card.

fetchEmiDetails

Method Usage:

PaytmCustomuisdk
     .fetchEmiDetails(cardType, channelCode)

Method Parameters:

Parameter

Description

Mandatory

channelCode

String

channelCode of card obtained from fetchBinDetails API(eg. VISA, MASTER)

Yes

cardType

String

type of card (DEBIT_CARD, CREDIT_CARD)

Yes

getLastNBSavedBank: This method is used to fetch the bank code through which the last successful Netbanking transaction was done.

getLastNBSavedBank

Method Usage:

PaytmCustomuisdk
     .getLastNBSavedBank()

Response:

This method will return a string parameter.

Value	Description
"ICICI"	If a user has used ICICI bank in his last net banking transaction

getLastSavedVPA: This method is used to fetch the VPA through which the last UPI Collect transaction was done by the user.

getLastSavedVPA

Method Usage:

PaytmCustomuisdk.getLastSavedVPA()

Response:

This method will return a string parameter.

Value	Description
"abc@xyz"	If a user has used this VPA in his last UPI collect transaction

isAuthCodeValid (For Android Only): This method is used to check if the fetched authcode is valid or not.

isAuthCodeValid

Method Usage:

PaytmCustomuisdk
     .isAuthCodeValid(clientId, authCode)

Method Parameters:

Parameter

Description

Mandatory

clientId

String

The clientId issued from Paytm identifying a merchant

Yes

authCode

String

authcode got from fetchAuthCode method

Yes

Response: Boolean

Parameter	Description
True	In case, auth code is valid which was fetched from fetchAuthCode method.
False	In case, auth code is not valid which was fetched from fetchAuthCode method.

checkHasInstrument (For Android Only): This method is called to check if the user has any saved instruments.

checkHasInstrument

Method Usage:

PaytmCustomuisdk
     .checkHasInstrument(mid)

Method Parameters:

Parameter

Description

Mandatory

mid

String

Merchant id identifying a merchant

Yes

Response: Boolean

Parameter	Description
True	In case, Paytm app is installed and the merchant has payment instrument
False	In case, Paytm app is not installed or merchant doesn’t have any payment instrument

setEnvironment: This method is used to change the PG environment from production to staging.

setEnvironment

Method Usage:

PaytmCustomuisdk.setEnvironment(environment)

Method Parameters:

Attribute

Description

Mandatory

environment

String

Current environment (STAGING / PRODUCTION)

Yes

getEnvironment: This method is called to check the current environment.

getEnvironment

Method Usage:

PaytmCustomuisdk.getEnvironment()

PaytmConsentCheckbox: This method is used to customize the consent checkbox as per your theme and requirement.

PaytmConsentCheckbox

View Properties:

Properties	Description
tintColor object	true - when checkbox is selected for color false - when checkbox is unselected for color
style object	fontFamily - use font exact font name as in your assets/fonts directory. For example: fonts/Entypo-Bold.ttf => fontFamily : "Entypo-Bold" color - to set text color backgroundColor - color to set background color fontSize - to set text size

Properties

Description

tintColor

object

true - when checkbox is selected for color
false - when checkbox is unselected for color

style

object

fontFamily - use font exact font name as in your assets/fonts directory.
For example: fonts/Entypo-Bold.ttf => fontFamily : "Entypo-Bold"
color - to set text color
backgroundColor - color to set background color
fontSize - to set text size

Use the properties as below:

<PaytmConsentCheckBox
    tintColor ={
        {
            true: "blue", 
            false:"black"
        }
    }
    style ={
      {
        fontFamily:     "Entypo", 
        fontSize:       "18", 
        backgroundColor:"white", 
        padding:        "24", 
        color:          "black"
      }
    }     
   onChange={(e: boolean)=>setCheck(e)}
 />

Parameter	Description	Mandatory
cardNumber String	card number digits for a new card	Yes
cardExpiry String	card expiry date in the format MM/YY (eg. 11/19)	Yes
cardType String	type of card (DEBIT_CARD, CREDIT_CARD)	Yes
cardCvv String	CVV of the card	Yes
paymentFlow String	current payment flow (NONE, HYBRID, ADDNPAY)	Yes
authMode String	the mode of 2FA chosen for the card (either by 'pin' or 'OTP'), options obtained from fetchBinDetails API	Yes
channelCode String	channel code of card obtained from fetchBinDetails API(eg. VISA, MASTER)	Yes
bankCode String	bank code of card obtained from fetchBinDetails API(eg. ICICI, AXIS)	Yes
issuingBankCode String	bank code of card obtained from fetchBinDetails API(eg. ICICI, AXIS)	Yes
emiChannelId String	EMI Plan id in case of an EMI transaction	No
saveCard Boolean	flag to indicate if the new card should be saved at Paytm’s end	Yes

Parameter	Description	Mandatory
cardId String	cardId for a saved card	Yes
cardType String	type of card (DEBIT_CARD, CREDIT_CARD)	Yes
cardCvv String	CVV of the card	Yes
paymentFlow String	current payment flow (NONE, HYBRID, ADDNPAY)	Yes
authMode String	the mode of 2FA chosen for the card (either by 'pin' or 'OTP'), options obtained from fetchBinDetails API	Yes
channelCode String	channel code of card obtained from fetchBinDetails API(eg. VISA, MASTER)	Yes
issuingBankCode String	bank code of card obtained from fetchBinDetails API(eg. ICICI, AXIS)	Yes
emiChannelId String	EMI Plan id in case of an EMI transaction	No

Attribute	Description	Mandatory
paymentFlow String	current payment flow (NONE, ADDANDPAY)	Yes
bankAccountJson Object	Json object representing a bank account for UPI	Yes
vpaName String	Virtual Payment Adress(eg.xyz@paytm)	Yes
merchantDetailsJson Object	Json object containing merchant info for which payment is required	Yes