Inventory Concepts

In this document, you’ll learn about the main concepts in the Inventory Module, and how data is stored and related.

InventoryItem

An inventory item, represented by the InventoryItem data model, is a stock-kept item, such as a product, whose inventory can be managed.

The InventoryItem data model mainly holds details related to the underlying stock item, but has relations to other data models that include its inventory details.

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InventoryLevel

An inventory level, represented by the InventoryLevel data model, holds the inventory and quantity details of an inventory item in a specific location.

It has three quantity-related attributes:

• stocked_quantity: The available stock quantity of an item in the associated location.
• reserved_quantity: The quantity reserved from the available stocked_quantity. It indicates the quantity that's still not removed from stock, but considered as unavailable when checking whether an item is in stock.
• incoming_quantity: The incoming stock quantity of an item into the associated location. This attribute doesn't play into the stocked_quantity or when checking whether an item is in stock.

Associated Location

The inventory level's location is determined by the location_id attribute. The Medusa application links the InventoryLevel data model with the StockLocation data model from the Stock Location Module.

Learn more about this relation in this guide

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ReservationItem

A reservation item, represented by the ReservationItem data model, represents unavailable quantity of an inventory item in a location. It's used when an order is placed but not fulfilled yet.

The reserved quantity is associated with a location, so it has a similar relation to that of the InventoryLevel with the Stock Location Module.