Using Back in Stock with products available to preorder

Pre-order items are product variants that are sold out but still available to purchase. 

Stores can set a variant to be able for pre-order in the Shopify admin for their store. Under products that can choose a variant and enable Allow customers to purchase this product when it’s out of stock. You can read more on how to enable it at this Shopify tutorial.

By default Back in Stock won’t:

  • appear for a pre-order product
  • send customer notifications for a pre-order product that has zero inventory

You can configure both of these settings as described below.

Displaying Back in Stock for products available to pre-order

If you would like Back in Stock to appear when a customer selects a variant available to pre-order:

  1. From your Back in Stock dashboard choose Customize
  2. Press 'Product page button' on the left hand drop-down
  3. Click on the 'Behavior' tab

Here we can see the option to show for 'pre-order' items and enable it, then press save.


Note: this configures the Back in Stock storefront widget button. If you have built a custom integration in your product template you may wish to check it designed to appear for a pre-order variant.

Resolving the ‘inventory_quantity not available’ message.

To determine if a product is pre-order the Back in Stock widget needs to read the inventory_quantity of a product from the online store. Some Shopify stores don’t allow access to the inventory_quantity so we have a theme helper snippet to work around this.

The theme helper snippet is installed automatically when you install Back in Stock. If the theme snippet is removed (for example, you have changed themes) and you have show  Show for pre-order items enabled you may see an error message in the browser console: 

[Back in Stock] Warning: inventory_quantity not available but show for preorder is enabled.

Additionally, the Back in Stock widget may not appear for the sold out variants.

To resolve this copy the filesnippets/back-in-stock-helper.liquid from your old theme to the new theme.  If you no longer have access to this snippet please contact [email protected] for assistance re-installing it.

Delivering customer notifications for pre-order products

Shopify allows products to be pre-order by setting "Allow customers to purchase when sold out" in the Shopify catalog. However, even when a product is available to purchase the default Back in Stock behavioris to only notify customer it is available if inventory is 1 or more.

You can configure Back in Stock to ignore inventory levels and send customer notifications whenever a product is available to purchase. This allows you to notify customers when a product is available to preorder, even if it is not yet in stock.

To configure your account to send customer notifications for pre-order product variants:


  1. From you Back in Stock dashboard choose 'Settings'
  2. Check the 'Send notifications for pre-order products' option
  3. Hit 'Save account details'

It may take a few minutes until the customer notifications are then sent.

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