diff --git a/modules/ppcp-googlepay/resources/js/GooglepayButton.js b/modules/ppcp-googlepay/resources/js/GooglepayButton.js
index f32d89e14..ae9120b52 100644
--- a/modules/ppcp-googlepay/resources/js/GooglepayButton.js
+++ b/modules/ppcp-googlepay/resources/js/GooglepayButton.js
@@ -28,12 +28,31 @@ import { PaymentMethods } from '../../../ppcp-button/resources/js/modules/Helper
  * @property {string} language - The locale; an empty string will apply the user-agent's language.
  */
 
+/**
+ * Google Pay JS SDK
+ *
+ * @see https://developers.google.com/pay/api/web/reference/request-objects
+ * @typedef {Object} GooglePaySDK
+ * @property {typeof PaymentsClient} PaymentsClient - Main API client for payment actions.
+ */
+
+/**
+ * The Payments Client class, generated by the Google Pay SDK.
+ *
+ * @see https://developers.google.com/pay/api/web/reference/client
+ * @typedef {Object} PaymentsClient
+ * @property {Function} createButton         - The convenience method is used to generate a Google Pay payment button styled with the latest Google Pay branding for insertion into a webpage.
+ * @property {Function} isReadyToPay         - Use the isReadyToPay(isReadyToPayRequest) method to determine a user's ability to return a form of payment from the Google Pay API.
+ * @property {Function} loadPaymentData      - This method presents a Google Pay payment sheet that allows selection of a payment method and optionally configured parameters
+ * @property {Function} onPaymentAuthorized  - This method is called when a payment is authorized in the payment sheet.
+ * @property {Function} onPaymentDataChanged - This method handles payment data changes in the payment sheet such as shipping address and shipping options.
+ */
+
 class GooglepayButton extends PaymentButton {
 	/**
 	 * Client reference, provided by the Google Pay JS SDK.
-	 * @see https://developers.google.com/pay/api/web/reference/client
 	 */
-	paymentsClient = null;
+	#paymentsClient = null;
 
 	constructor(
 		context,
@@ -90,6 +109,25 @@ class GooglepayButton extends PaymentButton {
 		return true;
 	}
 
+	/**
+	 * The Google Pay API.
+	 *
+	 * @return {?GooglePaySDK} API for the Google Pay JS SDK, or null when SDK is not ready yet.
+	 */
+	get googlePayApi() {
+		return window.google?.payments?.api;
+	}
+
+	/**
+	 * The Google Pay PaymentsClient instance created by this button.
+	 * @see https://developers.google.com/pay/api/web/reference/client
+	 *
+	 * @return {?PaymentsClient} The SDK object, or null when SDK is not ready yet.
+	 */
+	get paymentsClient() {
+		return this.#paymentsClient;
+	}
+
 	init( config = null, transactionInfo = null ) {
 		if ( this.isInitialized ) {
 			return;
@@ -114,12 +152,16 @@ class GooglepayButton extends PaymentButton {
 		this.baseCardPaymentMethod = this.allowedPaymentMethods[ 0 ];
 
 		super.init();
-		this.initClient();
+		this.#paymentsClient = this.createPaymentsClient();
 
 		if ( ! this.isPresent ) {
 			this.log( 'Payment wrapper not found', this.wrapperId );
 			return;
 		}
+		if ( ! this.paymentsClient ) {
+			this.log( 'Could not initialize the payments client' );
+			return;
+		}
 
 		this.paymentsClient
 			.isReadyToPay(
@@ -147,7 +189,11 @@ class GooglepayButton extends PaymentButton {
 		this.init();
 	}
 
-	initClient() {
+	createPaymentsClient() {
+		if ( ! this.googlePayApi ) {
+			return null;
+		}
+
 		const callbacks = {
 			onPaymentAuthorized: this.onPaymentAuthorized.bind( this ),
 		};
@@ -165,7 +211,7 @@ class GooglepayButton extends PaymentButton {
 		 *
 		 * @see https://developers.google.com/pay/api/web/reference/request-objects#PaymentOptions
 		 */
-		this.paymentsClient = new google.payments.api.PaymentsClient( {
+		return new this.googlePayApi.PaymentsClient( {
 			environment: this.buttonConfig.environment,
 			paymentDataCallbacks: callbacks,
 		} );
@@ -183,6 +229,10 @@ class GooglepayButton extends PaymentButton {
 	 * Add a Google Pay purchase button.
 	 */
 	addButton() {
+		if ( ! this.isInitialized ) {
+			return;
+		}
+
 		const baseCardPaymentMethod = this.baseCardPaymentMethod;
 		const { color, type, language } = this.style;