You've probably created a Bundle As a Product (BAP) and would like to know how the inventory works for the products in the bundle and for the bundle itself.

As you might have noticed when creating your BAP, there are three ways to set it up. To have it added to the cart as a single product (Single BAP), as its included products (Multi BAP), or as expanded line items connected to the product (Cart Transform) . What is the difference between Single-BAP and Multi-BAP?

Inventory handling depends on the BAP (Bundle as Product) type selected:

Fast Bundle automatically updates inventory levels for both the bundle product and the individual items included in the Single BAP.

When a customer purchases a bundle, the inventory of the Single BAP product itself is reduced by 1.

In addition to the main bundle product, the inventory of the individual items inside the bundle will also decrease when the order is paid or authorized.
​

For both Multi BAP and Cart Transform types, inventory is tracked only at the individual product level.

- When a customer places an order for a bundle, the inventory of each included product will be reduced by 1 as soon as the order is paid or authorized.

Multi BAP and Cart Transform refer to the bundle setup when you select one of the following options for your Bundle as a Product (BAP):

In this case, Fast Bundle creates a placeholder (dummy) product and sets a default SKU for it in the Shopify panel.

You will notice that when you create a Multi BAP or Cart Transform, on your Shopify admin in the Products section, the inventory of this bundle as a product will not be tracked:

The reason for this is that this product is a dummy product and will not actually ever be added to the cart and bought. Instead, if added correctly, the individual products in the bundle will be added to the cart and placed in the order. The SKU is not to be used for inventory purposes, and changing it will result in it bouncing back.

Read here to see how the Multi BAP and Cart Transform can get incorrectly added to the cart.

Since the actual products in the bundle are getting added to the cart, the inventory of the individual items will be correctly updated. The product itself does not have its inventory tracked, so no updates will be applied to it.

The way bundle items appear in the order details depends on the BAP type used:

Multi BAP

In Multi BAP, the SKUs of the individual products included in the bundle are listed separately in the order details, and each product appears as a standalone item.

Cart Transform

In Cart Transform, all bundle items are shown as separate line items in the order summary. The total bundle discount is automatically distributed across these items.
Under each item's SKU, you'll see a label such as "Part of: [bundle name]", which clearly indicates which bundle the item belongs to. While there are no specific discount tags on the line items, this labeling system keeps the order organized and easy to interpret.

If you have chosen this setting for your Bundle as A Product, a single product will be created on Shopify for your bundle. Inventory will be tracked for this product.

Let's take the Black Friday Set as an example of a Single-BAP

When you click on the Add To Cart (ATC) button, the Bundle As a Product itself will be added to the cart.

The variants of this new product are the possible combinations of the variants in the items in the bundle.
​
So if a bundle is created of products, T-shirt sizes (Large, Medium), and Hat colors (Blue, Black, Red), the Single-BAP will have 6 variants:
​

Example: when the "Black Friday Set: Lee Straight Jean + Lexie Shirt" product gets bought by a user, the inventory level of the "Black Friday Set", "Lee Straight Jean", and the "Lexie Shirt" will be decreased by one automatically, and the order will be like the image below:

As you can see, the individual item SKUs aren't displayed in order. Our Enterprise plan includes a feature called the "Single-BAP order action" that splits the Single-BAP in your order into its constituent items, showing its SKUs. To learn more about this feature and the conditions required for activation, please refer to our detailed guide on the Single-BAP order action.

The inventory of the Single-BAP will reflect the minimum availability of the individual items included in the bundle.

Example:

The possible combinations would be:

In short, the inventory of both the BAP product and its included products will be updated correctly, and these two will always be in sync.

We hope this article was helpful! If you have any further questions or need additional assistance, don’t hesitate to reach out to the Fast Bundle support team. You can contact us through the following options:

We’re always here to assist you!