Held inventory is a very interesting feature that has to be handled by every single online ecommerce shopping cart site.

Held inventory is the term used to represent the inventory of the items that people keep in their shopping cart for longer durations.

Here is an example.

Lets assume there is a product P1 and it has two pieces left in the inventory.

On the site visitor V1 and V2 go and add the item to their cart. They have not yet purchased the item. At this point of time:

- There are two items in stock

- There are zero items in the online inventory

Now if the visitor V1 places the order then at this point of time:

- There is one item in stock

- There are zero items in the online inventory.

Assume the visitor V2 did not do anything with the inventory and went out. If V2 never returned to place the order, then our site will continue to say ‘Item Not In Stock’.

To avoid this situation, there are a few solutions.

Solution 1: Held Inventory Expiration:

Using this concept, the administrator of the cart can set a expiration time for inventory that is not sold – and then put the item back in the inventory after this time. This could be ideally six hours or twelve hours or twenty four hours or some other value, all based on the nature of the products in the business.

Using this model, if the administator sets the expiration as six hours, after six hours the product will be restored into the inventory. When Visitor V2 comes to the site again, their cart would have expired and it will ask them to add it to cart again, if they try to checkout using this produc that the chose many hours earlier.

The advantage of this model is that it is very simple and easy to manage.

The disadvantage is that until the ‘expiration’ happens, the products selected in the cart by the visitors are out of inventory – thus giving a possibility for misuse.

Solution 2: Real Order Inventory:

In this model, the inventory is only deducted if a real order is placed.  This way visitor V1 and V2 can take the same product at the same time and add it to their cart. If there is one item in the inventory, if both of them

On the product page, when a visitor tries to close the browser or leave the page, with products in their inventory, they are prompted with a message saying ‘There are items in the inventory which will be removed from your cart. Confirm Yes/No’.

If you are using any other technique, I would love to know it. Do comment and reply.