diff --git a/app/code/Magento/CatalogInventory/Model/StockStateProvider.php b/app/code/Magento/CatalogInventory/Model/StockStateProvider.php
index 4cffc678314b..7209f5f23b3a 100644
--- a/app/code/Magento/CatalogInventory/Model/StockStateProvider.php
+++ b/app/code/Magento/CatalogInventory/Model/StockStateProvider.php
@@ -3,6 +3,7 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
 
 // @codingStandardsIgnoreFile
 
@@ -14,6 +15,7 @@
 use Magento\Framework\Locale\FormatInterface;
 use Magento\Framework\Math\Division as MathDivision;
 use Magento\Framework\DataObject\Factory as ObjectFactory;
+use Magento\InventorySales\Model\GetProductQuantityInterface;
 
 /**
  * Interface StockStateProvider
@@ -45,11 +47,17 @@ class StockStateProvider implements StockStateProviderInterface
      */
     protected $qtyCheckApplicable;
 
+    /**
+     * @var GetProductQuantityInterface
+     */
+    private $getProductQuantity;
+
     /**
      * @param MathDivision $mathDivision
      * @param FormatInterface $localeFormat
      * @param ObjectFactory $objectFactory
      * @param ProductFactory $productFactory
+     * @param GetProductQuantityInterface $getProductQuantity
      * @param bool $qtyCheckApplicable
      */
     public function __construct(
@@ -57,6 +65,7 @@ public function __construct(
         FormatInterface $localeFormat,
         ObjectFactory $objectFactory,
         ProductFactory $productFactory,
+        GetProductQuantityInterface $getProductQuantity,
         $qtyCheckApplicable = true
     ) {
         $this->mathDivision = $mathDivision;
@@ -64,6 +73,7 @@ public function __construct(
         $this->objectFactory = $objectFactory;
         $this->productFactory = $productFactory;
         $this->qtyCheckApplicable = $qtyCheckApplicable;
+        $this->getProductQuantity = $getProductQuantity;
     }
 
     /**
@@ -72,11 +82,14 @@ public function __construct(
      */
     public function verifyStock(StockItemInterface $stockItem)
     {
-        if ($stockItem->getQty() === null && $stockItem->getManageStock()) {
+//        prototype code
+//        $productQty = $this->getProductQuantity->execute($stockItem);
+        $productQty = $stockItem->getQty();
+        if ($productQty === null && $stockItem->getManageStock()) {
             return false;
         }
         if ($stockItem->getBackorders() == StockItemInterface::BACKORDERS_NO
-            && $stockItem->getQty() <= $stockItem->getMinQty()
+            && $productQty <= $stockItem->getMinQty()
         ) {
             return false;
         }
@@ -89,7 +102,7 @@ public function verifyStock(StockItemInterface $stockItem)
      */
     public function verifyNotification(StockItemInterface $stockItem)
     {
-        return (float)$stockItem->getQty() < $stockItem->getNotifyStockQty();
+        return $this->getProductQuantity->execute($stockItem) < $stockItem->getNotifyStockQty();
     }
 
     /**
@@ -166,10 +179,11 @@ public function checkQuoteItemQty(StockItemInterface $stockItem, $qty, $summaryQ
             $result->setHasError(true)->setMessage($message)->setQuoteMessage($message)->setQuoteMessageIndex('qty');
             return $result;
         } else {
-            if ($stockItem->getQty() - $summaryQty < 0) {
+            $productQty = $this->getProductQuantity->execute($stockItem);
+            if ($productQty - $summaryQty < 0) {
                 if ($stockItem->getProductName()) {
                     if ($stockItem->getIsChildItem()) {
-                        $backOrderQty = $stockItem->getQty() > 0 ? ($summaryQty - $stockItem->getQty()) * 1 : $qty * 1;
+                        $backOrderQty = $productQty > 0 ? ($summaryQty - $productQty) * 1 : $qty * 1;
                         if ($backOrderQty > $qty) {
                             $backOrderQty = $qty;
                         }
@@ -179,7 +193,7 @@ public function checkQuoteItemQty(StockItemInterface $stockItem, $qty, $summaryQ
                         $orderedItems = (int)$stockItem->getOrderedItems();
 
                         // Available item qty in stock excluding item qty in other quotes
-                        $qtyAvailable = ($stockItem->getQty() - ($summaryQty - $qty)) * 1;
+                        $qtyAvailable = ($productQty - ($summaryQty - $qty)) * 1;
                         if ($qtyAvailable > 0) {
                             $backOrderQty = $qty * 1 - $qtyAvailable;
                         } else {
@@ -241,7 +255,7 @@ public function checkQty(StockItemInterface $stockItem, $qty)
         if (!$stockItem->getManageStock()) {
             return true;
         }
-        if ($stockItem->getQty() - $stockItem->getMinQty() - $qty < 0) {
+        if ($this->getProductQuantity->execute($stockItem) - $stockItem->getMinQty() - $qty < 0) {
             switch ($stockItem->getBackorders()) {
                 case \Magento\CatalogInventory\Model\Stock::BACKORDERS_YES_NONOTIFY:
                 case \Magento\CatalogInventory\Model\Stock::BACKORDERS_YES_NOTIFY:
@@ -277,7 +291,10 @@ public function suggestQty(StockItemInterface $stockItem, $qty)
         $minQty = max($stockItem->getMinSaleQty(), $qtyIncrements);
         $divisibleMin = ceil($minQty / $qtyIncrements) * $qtyIncrements;
 
-        $maxQty = min($stockItem->getQty() - $stockItem->getMinQty(), $stockItem->getMaxSaleQty());
+        $maxQty = min(
+            $this->getProductQuantity->execute($stockItem) - $stockItem->getMinQty(),
+            $stockItem->getMaxSaleQty()
+        );
         $divisibleMax = floor($maxQty / $qtyIncrements) * $qtyIncrements;
 
         if ($qty < $minQty || $qty > $maxQty || $divisibleMin > $divisibleMax) {
@@ -343,7 +360,7 @@ public function getStockQty(StockItemInterface $stockItem)
             $product->load($stockItem->getProductId());
             // prevent possible recursive loop
             if (!$product->isComposite()) {
-                $stockQty = $stockItem->getQty();
+                $stockQty = $this->getProductQuantity->execute($stockItem);
             } else {
                 $stockQty = null;
                 $productsByGroups = $product->getTypeInstance()->getProductsToPurchaseByReqGroups($product);
diff --git a/app/code/Magento/CatalogInventory/Test/Unit/Model/Spi/StockStateProviderTest.php b/app/code/Magento/CatalogInventory/Test/Unit/Model/Spi/StockStateProviderTest.php
index 5c75249b7cbf..c2d69986af50 100644
--- a/app/code/Magento/CatalogInventory/Test/Unit/Model/Spi/StockStateProviderTest.php
+++ b/app/code/Magento/CatalogInventory/Test/Unit/Model/Spi/StockStateProviderTest.php
@@ -7,6 +7,7 @@
 
 use Magento\CatalogInventory\Api\Data\StockItemInterface;
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager as ObjectManagerHelper;
+use Magento\InventorySales\Model\GetProductQuantityInterface;
 
 /**
  * Class StockStateProviderTest
@@ -48,6 +49,11 @@ class StockStateProviderTest extends \PHPUnit\Framework\TestCase
      */
     protected $objectFactory;
 
+    /**
+     * @var \Magento\InventorySales\Model\GetProductQuantityInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    protected $getProductQuantity;
+
     /**
      * @var \Magento\Framework\DataObject|\PHPUnit_Framework_MockObject_MockObject
      */
@@ -130,6 +136,8 @@ protected function setUp()
         $this->productFactory = $this->createPartialMock(\Magento\Catalog\Model\ProductFactory::class, ['create']);
         $this->productFactory->expects($this->any())->method('create')->willReturn($this->product);
 
+        $this->getProductQuantity = $this->createPartialMock(GetProductQuantityInterface::class, ['execute']);
+
         $this->stockStateProvider = $this->objectManagerHelper->getObject(
             \Magento\CatalogInventory\Model\StockStateProvider::class,
             [
@@ -137,6 +145,7 @@ protected function setUp()
                 'localeFormat' => $this->localeFormat,
                 'objectFactory' => $this->objectFactory,
                 'productFactory' => $this->productFactory,
+                'getProductQuantity' => $this->getProductQuantity,
                 'qtyCheckApplicable' => $this->qtyCheckApplicable
             ]
         );
@@ -154,6 +163,7 @@ protected function tearDown()
      */
     public function testVerifyStock(StockItemInterface $stockItem, $expectedResult)
     {
+        $this->getProductQuantity->expects($this->any())->method('execute')->willReturn($stockItem->getQty());
         $this->assertEquals(
             $expectedResult,
             $this->stockStateProvider->verifyStock($stockItem)
@@ -167,6 +177,7 @@ public function testVerifyStock(StockItemInterface $stockItem, $expectedResult)
      */
     public function testVerifyNotification(StockItemInterface $stockItem, $expectedResult)
     {
+        $this->getProductQuantity->expects($this->any())->method('execute')->willReturn($stockItem->getQty());
         $this->assertEquals(
             $expectedResult,
             $this->stockStateProvider->verifyNotification($stockItem)
@@ -193,6 +204,7 @@ public function testCheckQty(StockItemInterface $stockItem, $expectedResult)
      */
     public function testSuggestQty(StockItemInterface $stockItem, $expectedResult)
     {
+        $this->getProductQuantity->expects($this->any())->method('execute')->willReturn($stockItem->getQty());
         $this->assertEquals(
             $expectedResult,
             $this->stockStateProvider->suggestQty($stockItem, $this->qty)
diff --git a/app/code/Magento/InventoryCatalog/etc/di.xml b/app/code/Magento/InventoryCatalog/etc/di.xml
index 34e0b6acc5c3..b5e9cb5137b4 100644
--- a/app/code/Magento/InventoryCatalog/etc/di.xml
+++ b/app/code/Magento/InventoryCatalog/etc/di.xml
@@ -11,30 +11,24 @@
     <preference for="Magento\InventoryCatalog\Model\GetProductIdsBySkusInterface" type="Magento\InventoryCatalog\Model\GetProductIdsBySkus"/>
     <preference for="Magento\InventoryCatalog\Model\GetSkusByProductIdsInterface" type="Magento\InventoryCatalog\Model\GetSkusByProductIds"/>
     <type name="Magento\InventoryApi\Api\StockRepositoryInterface">
-        <plugin name="prevent_default_stock_deleting"
-                type="Magento\InventoryCatalog\Plugin\InventoryApi\StockRepository\PreventDeleting\DefaultStockPlugin"/>
+        <plugin name="prevent_default_stock_deleting" type="Magento\InventoryCatalog\Plugin\InventoryApi\StockRepository\PreventDeleting\DefaultStockPlugin"/>
     </type>
     <type name="Magento\InventoryApi\Api\AssignSourcesToStockInterface">
-        <plugin name="prevent_assign_sources_to_default_stock"
-                type="Magento\InventoryCatalog\Plugin\InventoryApi\AssignSourcesToStock\PreventAssignSourcesToDefaultStockPlugin"/>
+        <plugin name="prevent_assign_sources_to_default_stock" type="Magento\InventoryCatalog\Plugin\InventoryApi\AssignSourcesToStock\PreventAssignSourcesToDefaultStockPlugin"/>
     </type>
     <type name="Magento\InventoryApi\Api\SourceItemsSaveInterface">
-        <plugin name="set_data_to_legacy_catalog_inventory_at_source_items_save"
-                type="Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin"/>
+        <plugin name="set_data_to_legacy_catalog_inventory_at_source_items_save" type="Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin"/>
     </type>
     <type name="Magento\InventoryApi\Api\SourceItemsDeleteInterface">
-        <plugin name="set_to_zero_legacy_catalog_inventory_at_source_items_delete"
-                type="Magento\InventoryCatalog\Plugin\InventoryApi\SetToZeroLegacyCatalogInventoryAtSourceItemsDeletePlugin"/>
+        <plugin name="set_to_zero_legacy_catalog_inventory_at_source_items_delete" type="Magento\InventoryCatalog\Plugin\InventoryApi\SetToZeroLegacyCatalogInventoryAtSourceItemsDeletePlugin"/>
     </type>
     <type name="Magento\InventoryApi\Api\AppendReservationsInterface">
-        <plugin name="apply_data_to_legacy_catalog_inventory_at_reservation_placing"
-                type="Magento\InventoryCatalog\Plugin\InventoryApi\ApplyDataToLegacyCatalogInventoryAtReservationPlacingPlugin"/>
+        <plugin name="apply_data_to_legacy_catalog_inventory_at_reservation_placing" type="Magento\InventoryCatalog\Plugin\InventoryApi\ApplyDataToLegacyCatalogInventoryAtReservationPlacingPlugin"/>
     </type>
     <type name="Magento\CatalogInventory\Model\ResourceModel\QtyCounterInterface">
         <plugin name="update_source_item_at_legacy_qty_counter" type="Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyQtyCounterPlugin"/>
     </type>
     <type name="Magento\CatalogInventory\Model\ResourceModel\Stock\Item">
-        <plugin name="update_source_item_at_legacy_stock_item_save"
-                type="Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyStockItemSavePlugin"/>
+        <plugin name="update_source_item_at_legacy_stock_item_save" type="Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyStockItemSavePlugin"/>
     </type>
 </config>
diff --git a/app/code/Magento/InventorySales/Model/GetProductQuantityInterface.php b/app/code/Magento/InventorySales/Model/GetProductQuantityInterface.php
new file mode 100644
index 000000000000..4eaa8c16d234
--- /dev/null
+++ b/app/code/Magento/InventorySales/Model/GetProductQuantityInterface.php
@@ -0,0 +1,24 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\InventorySales\Model;
+
+use Magento\CatalogInventory\Api\Data\StockItemInterface;
+
+/**
+ * Get Product Quantity from legacy catalog stock item
+ */
+interface GetProductQuantityInterface
+{
+
+    /**
+     * @param StockItemInterface $legacyStockItem
+     *
+     * @return float|null
+     */
+    public function execute(StockItemInterface $legacyStockItem);
+}
diff --git a/app/code/Magento/InventorySales/Model/ResourceModel/GetProductQuantity.php b/app/code/Magento/InventorySales/Model/ResourceModel/GetProductQuantity.php
new file mode 100644
index 000000000000..56b73cb6e666
--- /dev/null
+++ b/app/code/Magento/InventorySales/Model/ResourceModel/GetProductQuantity.php
@@ -0,0 +1,84 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\InventorySales\Model\ResourceModel;
+
+use Magento\CatalogInventory\Api\Data\StockItemInterface;
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\InventoryApi\Api\GetProductQuantityInStockInterface;
+use Magento\InventoryCatalog\Model\GetSkusByProductIdsInterface;
+use Magento\InventorySales\Model\GetProductQuantityInterface;
+use Magento\InventorySalesApi\Api\Data\SalesChannelInterface;
+use Magento\InventorySalesApi\Api\StockResolverInterface;
+use Magento\Store\Model\StoreManagerInterface;
+
+/**
+ * This resource model is responsible for retrieving Product Quantity from Legacy Catalog Stock Item
+ * by Stock Resolver. This model provides backward compatibility to Legacy Catalog Stock Item
+ */
+class GetProductQuantity implements GetProductQuantityInterface
+{
+    /**
+     * @var StoreManagerInterface
+     */
+    private $storeManager;
+
+    /**
+     * @var GetSkusByProductIdsInterface
+     */
+    private $getSkusByProductIds;
+
+    /**
+     * @var StockResolverInterface
+     */
+    private $stockResolver;
+
+    /**
+     * @var GetProductQuantityInStockInterface
+     */
+    private $getProductQuantityInStock;
+
+    /**
+     * @param StoreManagerInterface $storeManager
+     * @param GetSkusByProductIdsInterface $getSkusByProductIds
+     * @param StockResolverInterface $stockResolver
+     * @param GetProductQuantityInStockInterface $getProductQuantityInStock
+     */
+    public function __construct(
+        StoreManagerInterface $storeManager,
+        GetSkusByProductIdsInterface $getSkusByProductIds,
+        StockResolverInterface $stockResolver,
+        GetProductQuantityInStockInterface $getProductQuantityInStock
+    ) {
+        $this->storeManager = $storeManager;
+        $this->getSkusByProductIds = $getSkusByProductIds;
+        $this->stockResolver = $stockResolver;
+        $this->getProductQuantityInStock = $getProductQuantityInStock;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function execute(StockItemInterface $legacyStockItem)
+    {
+        try {
+            $websiteCode = $this->storeManager->getWebsite()->getCode();
+
+            $productIds = $this->getSkusByProductIds->execute([$legacyStockItem->getProductId()]);
+            $productSku = $productIds[$legacyStockItem->getProductId()];
+
+            $stock = $this->stockResolver->get(SalesChannelInterface::TYPE_WEBSITE, $websiteCode);
+
+            return $this->getProductQuantityInStock->execute($productSku, (int)$stock->getStockId());
+        } catch (NoSuchEntityException $e) {
+            return $legacyStockItem->getQty();
+        } catch (LocalizedException $e) {
+            return $legacyStockItem->getQty();
+        }
+    }
+}
diff --git a/app/code/Magento/InventorySales/etc/di.xml b/app/code/Magento/InventorySales/etc/di.xml
index d55b91612995..0f46b825e2cc 100644
--- a/app/code/Magento/InventorySales/etc/di.xml
+++ b/app/code/Magento/InventorySales/etc/di.xml
@@ -13,13 +13,13 @@
     <preference for="Magento\InventorySales\Ui\SalesChannelNameResolverInterface" type="Magento\InventorySales\Ui\WebsiteNameResolver"/>
     <preference for="Magento\InventorySales\Model\GetAssignedStockIdForWebsiteInterface" type="Magento\InventorySales\Model\ResourceModel\GetAssignedStockIdForWebsite"/>
     <preference for="Magento\InventorySales\Model\DeleteSalesChannelToStockLinkInterface" type="Magento\InventorySales\Model\ResourceModel\DeleteSalesChannelToStockLink"/>
+    <preference for="Magento\InventorySales\Model\GetProductQuantityInterface" type="Magento\InventorySales\Model\ResourceModel\GetProductQuantity"/>
     <preference for="Magento\InventorySalesApi\Api\StockResolverInterface" type="Magento\InventorySales\Model\StockResolver"/>
     <type name="Magento\InventoryApi\Api\StockRepositoryInterface">
         <plugin name="load_sales_channels_on_get_list" type="Magento\InventorySales\Plugin\InventoryApi\StockRepository\LoadSalesChannelsOnGetListPlugin"/>
         <plugin name="load_sales_channels_on_get" type="Magento\InventorySales\Plugin\InventoryApi\StockRepository\LoadSalesChannelsOnGetPlugin"/>
         <plugin name="save_sales_channels_links" type="Magento\InventorySales\Plugin\InventoryApi\StockRepository\SaveSalesChannelsLinksPlugin"/>
-        <plugin name="prevent_deleting_assigned_to_sales_channels_stock"
-                type="Magento\InventorySales\Plugin\InventoryApi\StockRepository\PreventDeletingAssignedToSalesChannelsStockPlugin"/>
+        <plugin name="prevent_deleting_assigned_to_sales_channels_stock" type="Magento\InventorySales\Plugin\InventoryApi\StockRepository\PreventDeletingAssignedToSalesChannelsStockPlugin"/>
     </type>
     <type name="Magento\Inventory\Ui\DataProvider\StockDataProvider">
         <plugin name="sales_channel_data" type="Magento\InventorySales\Plugin\Inventory\Ui\StockDataProvider\SalesChannels" />