webapi.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Webapi:etc/webapi.xsd">
    <route url="/V1/stockItems/:productSku" method="GET">
        <service class="Magento\CatalogInventory\Api\StockRegistryInterface" method="getStockItemBySku"/>
        <resources>
            <resource ref="Magento_CatalogInventory::cataloginventory"/>
        </resources>
    </route>
    <route url="/V1/products/:productSku/stockItems/:itemId" method="PUT">
        <service class="Magento\CatalogInventory\Api\StockRegistryInterface" method="updateStockItemBySku"/>
        <resources>
            <resource ref="Magento_CatalogInventory::cataloginventory"/>
        </resources>
    </route>
    <route url="/V1/stockItems/lowStock/" method="GET">
        <service class="Magento\CatalogInventory\Api\StockRegistryInterface" method="getLowStockItems"/>
        <resources>
            <resource ref="Magento_CatalogInventory::cataloginventory"/>
        </resources>
    </route>
    <route url="/V1/stockStatuses/:productSku" method="GET">
        <service class="Magento\CatalogInventory\Api\StockRegistryInterface" method="getStockStatusBySku"/>
        <resources>
            <resource ref="Magento_CatalogInventory::cataloginventory"/>
        </resources>
    </route>
</routes>