Before proceeding with this article, we suggest reading Managing bundles in Katana.

In Shopify, kits/bundles are typically created as separate products (either directly in Shopify or using any relevant add-on).

For each kit in Shopify, you can select whether to display the kit as available for sale for your customers even if the kit is out of stock, or remove the kit listing when the inventory level for the kit is zero. This means that you can either pre-define the total number of kits that are available for sales and remove them from your Shopify listing once they are sold out, or keep the kits available at all times. In the latter case, you would need to make those kits in Katana when the sales order comes in (read more about defining kits from the link above).

We suggest keeping the kit available at all times only if you are making the required products to order or, at least, have an opportunity to make more products when required. If you can only make a limited amount of product, you have a risk of overselling the product if it's available via kits at all times.

Some Katana users are looking to make the kits to stock to define the total number of kits available. In this case, you should create a Manufacturing order (MO) for the kit in Katana before the sales order for the kit comes in to add kits to your stock. When making kits, you also might create Manufacturing orders for the products required by kits to make more products for kits.

However, when you have an open MO for the kit in Katana, it will commit the required products to this MO. When you create additional Manufacturing orders for the required products in Katana, the Expected quantity in Katana for the products will increase.

When you have enabled the stock sync, the stock level synced to Shopify equals: In stock - Committed quantity in Katana. Read more here. This calculation does not take the Expected quantities for products into account, i.e. we only sync the stock of completed products that is available for sales.

This could potentially create a problem where the MO for the kit (that immediately commits the required products) reduces the available stock for those individual products also in Shopify, but the Expected quantity for the required products does not add stock to Shopify.

For that reason, the Committed quantity used in calculating the synced stock level does not include products that, in Katana, are part of kits, i.e. products that are committed as ingredients to other products. Otherwise, the individual products might be removed from your Shopify listing before the production of those products for the kit is complete, and you might lose sales.

This means that only the quantity of the product that appears directly on a Sales order (i.e. not the quantity that is required by any bundles on any Sales orders) is taken into account in the stock sync calculation.

In this case, if a sales order is received for a bundle, the Sales items availability for the kit is Not available as you are keeping zero kits in stock in Shopify and in Katana. Therefore, the quantities of products required for this bundle are committed directly to the sales order in Katana as ingredients. However, these commitments are not taken into account when syncing stock levels for individual products from Katana to Shopify.

Click Make to order for making the kit and complete then complete the MO for the kit to reduce the stock for related products. This reduction in stock for individual products is also synced to Shopify at the time of completing the MO. Now, you have the kit in stock and can fulfill the SO. Once the SO is fulfilled, the stock for the kit is reduced back to zero.