Google Pay™ Integration Guide for Merchants

Requirements and Policies

Merchants must comply with the following requirements:
- Google Pay API Terms of Service
- Google Pay Acceptable Use Policy
- Any other applicable Google Pay terms, policies, and guidelines

In addition, merchants must: Adhere to the Terms of Service, policies, and requirements established by their Payment Service Provider (PSP) Ensure their implementation complies with all applicable legal, regulatory, and contractual obligations

Integration

Merchants can integrate with the payment gateway in one of two ways:
- Payment 3DS: Payment processing is handled on the hosted payment page (HPP)
- ServerToServer: Payment processing is handled by the merchant's application using the payment gateway API

Payment 3DS (HPP - Hosted Payment Page)

Merchants using the Payment 3DS (HPP) integration are required to comply with the Google Pay and Wallet API's Acceptable Use Policy and must accept the terms defined in the Google Pay API Terms of Service before enabling Google Pay. Please ensure your integration meets all applicable Google Pay requirements.

Below is an example of our Hosted Payment Page (HPP). It allows customers to complete a payment using either Google Pay or a regular card payment. The appearance of the page can be customized to match the merchant's branding and visual style.



The Hosted Payment Page can either be embedded into the merchant's website using an iframe or displayed as a standalone page by redirecting the customer to the payment gateway's HPP.

Note: In order to enable Google Pay on the Hosted Payment Page, merchants must submit an integration request to the support team by using the application form available

		{
		  "version": "1",
		  "id": 12345678,
		  "password": "password",
		  "msgVerifier": "msgVerifier",
		  "langId": "USA",
		  "msgName": "PaymentInitRequest",
		  "action": 1,
		  "responseURL": "responseURL",
		  "errorURL": "errorURL",
		  "currencycode": "941",
		  "amt": "15",
		  "trackid": "trackid",
		  "payinst": "",
		  "recurAction": "",
		  "recurid": "recurid",
		  "recurContractId": "123456",
		  "cardSHA2": "Y",
		  "bankStmtFreeText": "123456",
		  "instructedFees": "123456",
		  "notificationFormat": "json",
		  "paymentPageMode": "0",
		  "buyerFirstName": "John",
		  "buyerLastName": "Smith",
		  "buyerUserId": "123456789",
		  "buyerPhoneNumber": "+381 62 123 4567",
		  "buyerEmailAddress": "john.smith@mail.com",
		  "clientIpAddress": "127.0.0.1",
		  "clientUserAgent": "Mozilla/4.0 (compatible; Win32; WinHttp.WinHttpRequest.5), accept=*/*",
		  "clientHttpHeaders": "connection=Keep-Alive content-type=application/x-www-form-urlencoded; Charset=UTF-8 accept=*/* user-agent=Mozilla/4.0 (compatible; Win32; WinHttp.WinHttpRequest.5) content-length=289 host=localhost:8080",
		  "udf1": "AA",
		  "udf2": "BB",
		  "udf3": "CC",
		  "udf4": "DD",
		  "udf5": "EE"
		}
		

		{
		  "type": "valid",
		  "msgName": "PaymentInitResponse",
		  "version": "1",
		  "msgDateTime": "2026-06-30 11:18:03.441",
		  "msgVerifier": "msgVerifier",
		  "paymentid": "123456789871161812",
		  "browserRedirectionURL": "browserRedirectionURL"
		}
	    

To request our HPP, send a PaymentInitRequest. The response will contain the browserRedirectionURL field, which specifies the URL to which the customer should be redirected to access the Hosted Payment Page (HPP).

To request this integration, please submit an integration request using the application form available here.

Our team will guide you through the onboarding process and provide all the necessary documentation and technical assistance required to complete the integration.

ServerToServer - (Payment gateway API)

Merchants using the ServerToServer integration are required to comply with the Google Pay and Wallet API's Acceptable Use Policy and must accept the terms defined in the Google Pay API Terms of Service before enabling Google Pay. Please ensure your integration meets all applicable Google Pay requirements.

ServerToServer integration allows merchants to handle the entire payment flow on their own website while communicating directly with the payment gateway through the API.

To request this integration, please submit an integration request using the application form available here.

Our team will guide you through the onboarding process and provide all the necessary documentation and technical assistance required to complete the integration.

After successfully testing the ServerToServer integration, merchants must request production access and publish their integration through the Google Pay & Wallet Console by following the official Publish your integration guide.

Endpoint Implementation

		{
		  "p_messageVersion": "1.0.5",
		  "messageType": "pPrq",
		  "id": "12345678",
		  "password": "password",
		  "action": 1,
		  "recurAction": "",
		  "recurid": null,
		  "trackid": "trackid",
		  "payinst": "VPAS",
		  "deviceChannel": "02",
		  "googlePayToken": "paymentData.paymentMethodData.tokenizationData.token",
		  "threeDSRequestorID": "123456789",
		  "threeDSRequestorURL": "123456789",
		  "threeDSRequestorStartProtocolVersion": "2.2.0",
		  "threeDSRequestorEndProtocolVersion": "2.3.1",
		  "purchaseAmount": "12300",
		  "msgVerifier": "msgVerifier"
		}
		

		{
		  "startRange": "1234567800000000",
		  "cardCurrencyCode": "941",
		  "p_messageVersion": "1.0.5",
		  "cardType": "M",
		  "threeDSServerStartProtocolVersion": "2.2.0",
		  "dsEndProtocolVersion": "2.2.0",
		  "threeDSServerEndProtocolVersion": "2.2.0",
		  "cardCountryCode": "688",
		  "messageType": "pPrs",
		  "paymentid": "929915200141461778",
		  "msgVerifier": "msgVerifier",
		  "endRange": "1234567899999999",
		  "threeDSMethodURL": "threeDSMethodURL",
		  "acsStartProtocolVersion": "2.2.0",
		  "acsEndProtocolVersion": "2.2.0",
		  "dsStartProtocolVersion": "2.1.0",
		  "threeDSServerTransID": "c766ed1c-f74d-4f2e-ab43-30efb5baf534"
		}
	    

		{
		  "acquirerMerchantID": "9876543210001",
		  "googlePayToken": "paymentData.paymentMethodData.tokenizationData.token",
		  "billAddrLine1": "billAddrLine1",
		  "billAddrLine2": "billAddrLine2",
		  "billAddrLine3": "billAddrLine3",
		  "billAddrPostCode": "11000",
		  "billAddrCity": "Belgrade",
		  "billAddrCountry": "SRB",
		  "browserAcceptHeader": "text/html",
		  "browserIP": "1.12.123.255",
		  "browserJavascriptEnabled": true,
		  "browserJavaEnabled": true,
		  "browserLanguage": "en",
		  "browserColorDepth": "32",
		  "browserScreenHeight": "1920",
		  "browserScreenWidth": "1020",
		  "browserTZ": "0",
		  "browserUserAgent": "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:47.0) Gecko/20100101 Firefox/47.0",
		  "cardExpiryDate": "3512",
		  "cardholderName": "John Smith",
		  "cardSecurityCode": "777",
		  "deviceChannel": "02",
		  "email": "john.smith@mail.com",
		  "mcc": "5964",
		  "messageCategory": "01",
		  "messageType": "pArq",
		  "messageVersion": "2.2.0",
		  "merchantCountryCode": "688",
		  "merchantName": "Merchant Service",
		  "p_messageVersion": "1.0.5",
		  "purchaseAmount": "15",
		  "purchaseCurrency": "978",
		  "purchaseDate": "20190627132429",
		  "purchaseExponent": "2",
		  "purchaseInstalData": null,
		  "recurNewCardExpDate": "205208",
		  "shipAddrLine1": "VIALE EUROPA 21",
		  "shipAddrLine2": "VIALE EUROPA 22",
		  "shipAddrLine3": "VIALE EUROPA 23",
		  "shipAddrCity": "Rome",
		  "shipAddrPostCode": "144",
		  "shipAddrCountry": "ITA",
		  "threeDSServerTransID": "replace-it-with-pPrs.threeDSServerTransID",
		  "notificationURL": "notificationURL",
		  "threeDSRequestorAuthenticationInd": "01",
		  "threeDSRequestorChallengeInd": "01",
		  "threeDSRequestorID": "661",
		  "threeDSRequestorName": "3DS Test Requestor",
		  "threeDSRequestorURL": "threeDSRequestorURL"
		}
	    

		{
		  "p_messageVersion": "1.0.5",
		  "messageType": "pArs",
		  "acsChallengeMandated": "Required if Transaction Status = C - Length 1 character - Values accepted Y, N.",
		  "acsOperatorID": "acsOperatorUL",
		  "acsReferenceNumber": "acsReferenceNumber",
		  "acsURL": "1234",
		  "authenticationType": "2",
		  "authenticationValue": "authenticationValue",
		  "dsReferenceNumber": "dsReferenceNumber",
		  "dsTransID": "dsTransID",
		  "eci": "2",
		  "transStatus": "Y",
		  "transStatusReason": "1",
		  "transStatusReasonInfo": "string",
		  "acsSignedContent": "string",
		  "acsDecConInd": "1234",
		  "whiteListStatus": "1234",
		  "whiteListStatusSource": "2",
		  "trustListStatus": "1234",
		  "trustListStatusSource": "2",
		  "deviceBindingStatus": "1",
		  "deviceBindingStatusSource": "1",
		  "deviceInfoRecognisedVersion": "2.1",
		  "transChallengeExemption": "5"
		}
	    

		{
		  "messageType": "pGcq",
		  "messageVersion": "2.2.0",
		  "challengeWindowSize": "5",
		  "p_messageVersion": "1.0.5",
		  "threeDSServerTransID": "replace-it-with-pPrs.threeDSServerTransID"
		}
	    

		{
		  "p_messageVersion": "1.0.5",
		  "messageType": "pGcs",
		  "messageVersion": "2.2.0",
		  "threeDSServerTransID": "c766ed1c-f74d-4f2e-ab43-30efb5baf534",
		  "htmlCreq": "htmlCreq"
		}
	    

		{
		  "messageType": "pCrq",
		  "messageVersion": "2.2.0",
		  "htmlCres": "htmlCres",
		  "p_messageVersion": "1.0.5",
		  "threeDSServerTransID": "replace-it-with-pPrs.threeDSServerTransID"
		}
	    

		{
		  "p_messageVersion": "1.0.5",
		  "messageType": "pCrs",
		  "messageVersion": "2.2.0",
		  "threeDSServerTransID": "c766ed1c-f74d-4f2e-ab43-30efb5baf534b",
		  "messageCategory": "1",
		  "authenticationType": "2",
		  "authenticationValue": "authenticationValue",
		  "dsReferenceNumber": "dsReferenceNumber",
		  "dsTransID": "dsTransID",
		  "eci": "2",
		  "transStatus": "Y",
		  "transStatusReason": "1",
		  "transStatusReasonInfo": "",
		  "interactionCounter": "2",
		  "challengeCancel": "1",
		  "challengeCompletionInd": "Y",
		  "acsCounterAtoS": "1234",
		  "acsHTML": "string",
		  "whiteListStatus": "1234",
		  "whiteListStatusSource": "2",
		  "authorizationResult": [
		    {
		      "action": 1,
		      "auth": "KVADIW",
		      "amt": "15",
		      "currencycode": "941",
		      "paymentID": "123456789987",
		      "result": "APPROVED",
		      "tranID": "987654321",
		      "trackid": "CTV-TEST-PureBuy-1",
		      "ref": "1122334455",
		      "responsecode": "00",
		      "responsedescription": "Approved",
		      "cardtype": "VISA",
		      "liability": "N",
		      "expDate": "1022",
		      "cardLastFourDigits": 0,
		      "cardCountry": "USA"
		    }
		  ]
		}
	    

First, send a "pPrq" message with the Google Pay token ("paymentData.paymentMethodData.tokenizationData.token") in the "googlePayToken" field. In the "pPrs" response, you will receive the unique transaction identifier ("threeDSServerTransID").

Next, send a "pArq" message to determine whether a challenge is required for the transaction. Include the "threeDSServerTransID" received in the "pPrs" response. If the "transStatus" field has the value "Y", additional step-up authentication (challenge) is required. If the value is "N", no additional step-up authentication is needed.

If a challenge is required, send a "pGcq" message using the "threeDSServerTransID" from the "pPrs" response and receive the corresponding "pGcs" response. Then, send a challenge request ("pCrq") including the same "threeDSServerTransID". The transaction is considered successful if "authorizationResult.result" is "APPROVED" and "authorizationResult.responseCode" is "00".

We support two Google Pay authentication methods, "PAN_ONLY" and "CRYPTOGRAM_3DS", which determine whether step-up authentication is required.

When using "PAN_ONLY", step-up authentication is always required. When using "CRYPTOGRAM_3DS", additional step-up authentication is generally not required, provided that the integration is configured correctly and the payment is authenticated through Google Pay.

	<!DOCTYPE html>
	<html lang="en">
	<head>
	  <meta charset="UTF-8">
	  <title>HTML example page</title>
	</head>
	
	<body>
	  <div id="gPayContainer"></div>
	
	  <script src="index.js"></script>
	
	  <script async
	    src="https://pay.google.com/gp/p/js/pay.js"
	    onload="onGooglePayLoaded()">
	  </script>
	
	</body>
	</html>
	    

Setting up Google Pay configuration

These are the parameters that need to be defined in the index.js file.

	const tokenizationSpecification = {
	  type: 'PAYMENT_GATEWAY',
	  parameters: {
	    gateway: 'a360',
	    gatewayMerchantId: 'mechantTestId'
	  }
	};
	 

const cardPaymentMethod = {
  type: 'CARD',
  tokenizationSpecification: tokenizationSpecification,
  parameters: {
    billingAddressRequired: true,
    billingAddressParameters: {
      phoneNumberRequired: true,
      format: 'MIN'
    },
    allowedCardNetworks: ['VISA', 'MASTERCARD'],
    allowedAuthMethods: ['PAN_ONLY', 'CRYPTOGRAM_3DS']
  }
};
	

const googlePayConfiguration = {
  apiVersion: 2,
  apiVersionMinor: 0,
  allowedPaymentMethods: [cardPaymentMethod]
};
	

Setting up GPay button

let googlePayClient;

function onGooglePayLoaded() {
  googlePayClient = new google.payments.api.PaymentsClient({
    environment: 'PRODUCTION'
  });

  googlePayClient.isReadyToPay(googlePayConfiguration)
    .then(response => {
      if (response.result) {
        createAndAddButton();
      } else {
        console.log("Cannot pay with Google Pay");
      }
    })
    .catch(error => console.log('isReadyToPay error: ', error));
}
    

function createAndAddButton() {
  const button = googlePayClient.createButton({
    onClick: onGooglePaymentButtonClick,
	buttonRadius: 10,
	buttonType: 'short',
	buttonSizeMode: 'fill'
  });

  document.getElementById('gPayContainer').appendChild(button);
}
    

function onGooglePaymentButtonClick() {	
  const paymentDataRequest = {
    ...googlePayConfiguration,
    merchantInfo: {
      merchantId: 'BCR2DN634341234',
      merchantName: 'Test Shop'
    },
    transactionInfo: {
      totalPriceStatus: 'FINAL',
      totalPrice: '15.00',
      currencyCode: 'EUR',
      countryCode: 'RS'
    }
  };

  googlePayClient.loadPaymentData(paymentDataRequest)
    .then(paymentData => processPaymentData(paymentData))
    .catch(error => console.log('loadPaymentData error: ', error));
}
    

function processPaymentData(paymentData) {
  const token = paymentData?.paymentMethodData?.tokenizationData?.token;

	if (!token) {
	    console.error("Google Pay token missing");
	    return;
	}
	
	$("#googlePayToken").val(btoa(token));
	$("#paymentForm").submit();
};
    

<body>

  ...

  <form id="paymentForm" action="[will be provided by gateway]" method="post">

    ...

    <input type="hidden" id="googlePayToken" name="googlePayToken" value="" />

    ...

  </form>

  ...

</body>

Add a hidden input field to the payment form to store the Google Pay token. Before submitting the form, set its value to "paymentData.paymentMethodData.tokenizationData.token". The token will then be submitted to the server as part of the form data.

For a comprehensive guide to Google Pay integration, including advanced configuration options and implementation details, see the Google Pay Web developer documentation .

Before going live, review the Integration Checklist to ensure that your implementation meets Google's requirements and best practices.