diff --git a/client/checkout/api/index.js b/client/checkout/api/index.js
index fee6f6ad476..b5e5c3ac546 100644
--- a/client/checkout/api/index.js
+++ b/client/checkout/api/index.js
@@ -470,7 +470,6 @@ export default class WCPayAPI {
 			return Promise.reject();
 		}
 
-		// TODO ~FR: send updated info to cart with cart token, and update accordingly.
 		return window.wp.apiFetch( {
 			method: 'POST',
 			path: '/wc/store/v1/cart/update-customer',
@@ -488,15 +487,21 @@ export default class WCPayAPI {
 	 * @param {Object} shippingOption Shipping option.
 	 * @return {Promise} Promise for the request to the server.
 	 */
-	paymentRequestUpdateShippingDetails( shippingOption ) {
-		return this.request(
-			getPaymentRequestAjaxURL( 'update_shipping_method' ),
-			{
-				security: getPaymentRequestData( 'nonce' )?.update_shipping,
-				shipping_method: [ shippingOption.id ],
-				is_product_page: getPaymentRequestData( 'is_product_page' ),
-			}
-		);
+	async paymentRequestUpdateShippingDetails( shippingOption ) {
+		if ( ! this.paymentRequestCartInfo ) {
+			return Promise.reject();
+		}
+
+		return window.wp.apiFetch( {
+			method: 'POST',
+			path: '/wc/store/v1/cart/select-shipping-rate',
+			headers: {
+				Nonce: this.paymentRequestCartInfo.nonce,
+				'Cart-Token': this.paymentRequestCartInfo.cartToken,
+			},
+			// TODO ~FR: send correct package id
+			data: { package_id: 0, rate_id: shippingOption.id },
+		} );
 	}
 
 	/**
@@ -573,12 +578,46 @@ export default class WCPayAPI {
 		// TODO ~FR: this is the juicy stuff
 		return window.wp.apiFetch( {
 			method: 'POST',
-			path: '/wc/store/v1/cart/add-item',
+			path: '/wc/store/v1/checkout',
 			headers: {
 				Nonce: this.paymentRequestCartInfo.nonce,
 				'Cart-Token': this.paymentRequestCartInfo.cartToken,
 			},
-			data: productData,
+			data: {
+				customer_note: paymentData.order_comments,
+				billing_address: {
+					first_name: paymentData.billing_first_name,
+					last_name: paymentData.billing_last_name,
+					// TODO ~FR
+					company: '',
+					address_1: paymentData.billing_address_1,
+					address_2: paymentData.billing_address_2,
+					city: paymentData.billing_city,
+					state: paymentData.billing_state,
+					postcode: paymentData.billing_postcode,
+					country: paymentData.billing_country,
+					email: paymentData.billing_email,
+					phone: paymentData.billing_phone,
+				},
+				payment_method: 'woocommerce_payments',
+				payment_data: [
+					{
+						// TODO ~FR
+						key: 'payment_request_type',
+						value: paymentData.payment_request_type,
+					},
+					{
+						// TODO ~FR
+						key: 'wcpay-fraud-prevention-token',
+						value: paymentData[ 'wcpay-fraud-prevention-token' ],
+					},
+					{
+						// TODO ~FR
+						key: 'wcpay-payment-method',
+						value: paymentData[ 'wcpay-payment-method' ],
+					},
+				],
+			},
 		} );
 	}
 
diff --git a/client/payment-request/event-handlers.js b/client/payment-request/event-handlers.js
index 7ff449a10d1..c56fb28490c 100644
--- a/client/payment-request/event-handlers.js
+++ b/client/payment-request/event-handlers.js
@@ -9,27 +9,45 @@ import {
 } from './utils';
 
 export const shippingAddressChangeHandler = async ( api, event ) => {
-	// TODO ~FR: send updated info to cart with cart token, and update accordingly.
 	const response = await api.paymentRequestCalculateShippingOptions(
 		normalizeShippingAddress( event.shippingAddress )
 	);
 
 	// Possible statuses success, fail, invalid_payer_name, invalid_payer_email, invalid_payer_phone, invalid_shipping_address.
 	event.updateWith( {
+		// TODO ~FR: correct status
 		status: 'success',
-		// TODO ~FR: it shouldn't be a problem for product pages, but on cart pages with potentially multiple packages, things might get sketchy.
+		// TODO ~FR: it shouldn't be a problem for product pages,
+		//  but on cart pages with potentially multiple packages, things might get sketchy.
 		shippingOptions: response.shipping_rates[ 0 ].shipping_rates.map(
 			( rate ) => ( {
 				id: rate.rate_id,
 				label: rate.name,
-				amount: rate.price,
+				amount: parseInt( rate.price, 10 ),
+				detail: '',
 			} )
 		),
-		total: response.totals.total_price,
-		displayItems: response.items.map( ( item ) => ( {
-			label: item.name,
-			amount: item.prices.price,
-		} ) ),
+		total: {
+			label: '', // TODO ~FR,
+			amount: parseInt( response.totals.total_price, 10 ),
+			pending: false,
+		},
+		displayItems: [
+			...response.items.map( ( item ) => ( {
+				label: item.name,
+				amount: parseInt( item.prices.price, 10 ),
+			} ) ),
+			{
+				// TODO ~FR,
+				label: 'Tax',
+				amount: parseInt( response.totals.total_tax, 10 ),
+			},
+			{
+				// TODO ~FR,
+				label: 'Shipping',
+				amount: parseInt( response.totals.total_shipping, 10 ),
+			},
+		],
 	} );
 };
 
@@ -39,17 +57,31 @@ export const shippingOptionChangeHandler = async ( api, event ) => {
 		event.shippingOption
 	);
 
-	if ( response.result === 'success' ) {
-		event.updateWith( {
-			status: 'success',
-			total: response.total,
-			displayItems: response.displayItems,
-		} );
-	}
-
-	if ( response.result === 'fail' ) {
-		event.updateWith( { status: 'fail' } );
-	}
+	event.updateWith( {
+		// TODO ~FR: correct status
+		status: 'success',
+		total: {
+			label: '', // TODO ~FR,
+			amount: parseInt( response.totals.total_price, 10 ),
+			pending: false,
+		},
+		displayItems: [
+			...response.items.map( ( item ) => ( {
+				label: item.name,
+				amount: parseInt( item.prices.price, 10 ),
+			} ) ),
+			{
+				// TODO ~FR,
+				label: 'Tax',
+				amount: parseInt( response.totals.total_tax, 10 ),
+			},
+			{
+				// TODO ~FR,
+				label: 'Shipping',
+				amount: parseInt( response.totals.total_shipping, 10 ),
+			},
+		],
+	} );
 };
 
 const paymentResponseHandler = async (
@@ -59,21 +91,25 @@ const paymentResponseHandler = async (
 	abortPayment,
 	event
 ) => {
-	if ( response.result !== 'success' ) {
+	if ( response.payment_result.payment_status !== 'success' ) {
 		return abortPayment(
 			event,
+			// TODO ~FR
 			getErrorMessageFromNotice( response.messages )
 		);
 	}
 
 	try {
-		const confirmationRequest = api.confirmIntent( response.redirect );
+		const confirmationRequest = api.confirmIntent(
+			response.payment_result.redirect_url
+		);
 		// We need to call `complete` outside of `completePayment` to close the dialog for 3DS.
 		event.complete( 'success' );
 
+		// TODO ~FR: handle 3ds
 		// `true` means there is no intent to confirm.
 		if ( confirmationRequest === true ) {
-			completePayment( response.redirect );
+			completePayment( response.payment_result.redirect_url );
 		} else {
 			const redirectUrl = await confirmationRequest;