You can fetch product stock-related data like Qty, status, manage stock by REST API V1/stockItems/:SKU
URL: <BASE_URL>/rest/V1/stockItems/:SKU (https://magento246.test/rest/V1/stockItems/MySku)
Header: Authorization:Bearer <ADMIN_TOKEN>
Action: GET
Payload: none
Response:
{ "item_id": 12, "product_id": 8525, "stock_id": 1, "qty": 3, "is_in_stock": true, "is_qty_decimal": false, "show_default_notification_message": false, "use_config_min_qty": true, "min_qty": 0, "use_config_min_sale_qty": 1, "min_sale_qty": 1, "use_config_max_sale_qty": true, "max_sale_qty": 1000, "use_config_backorders": true, "backorders": 0, "use_config_notify_stock_qty": true, "notify_stock_qty": 1, "use_config_qty_increments": true, "qty_increments": 0, "use_config_enable_qty_inc": true, "enable_qty_increments": false, "use_config_manage_stock": true, "manage_stock": true, "low_stock_date": null, "is_decimal_divided": false, "stock_status_changed_auto": 0 }
In the response, item_id will be used to update specific product stock data.
All the data coming from the table, cataloginventory_stock_item
You can see only stock-related data in a response. Instead of calling Get Product API to fetch all the product data, Given API will be used in a situation where we need only inventory-related stuff.