Hi @peterbrunton, welcome to the community.
With a lot of disclaimers and “you’re playing with fire” warnings, you *can* technically do this with abundant caution by implementing your own Custom Catalog feed, inventory, and an adjacent Custom Back in Stock implementation. This is how typically one would do this if you’re not on a supported platform and trying to implement this feature for a custom ecommerce solution. I’m not sure how this might interfere or even conflict with the Shopify + Klaviyo native implementation of it, so you’ll need to QA it carefully. But you’re essentially creating your own back in stock, custom catalog “digital twin” of the Shopify inventory management and working off of the digital twin instead.
Note, all the front end part of adding users to the waitlist, the logic of checking the inventory status etc, may require your own custom development. See here:
You have full control of (and responsibility for) when, where, and how the trigger button appears; the appearance, text, and behavior of the modal; and all other aspects of the feature's behavior and appearance within your application.
So it can be done, but definitely requires a fair amount of development work.
Another way to do this, if your products come back in manageable frequency, is to just create your own Subscribe Form with a hidden dynamic parameter for the item (SKU or ProductID) and subscribe folks to a List. When a product come back in stock, create a Segment of folks for that particular product and send a Campaign email to those who were waiting. It won’t have the elegance of throttled batches of emails with automated time delay between each batch - you may have to do this manually, but it’s a nice work around that doesn’t require you to do complex developer implementation.
Obviously if you have dozens or hundreds of products going in and out of stock constantly this becomes a manual burden - but if only a handful of items go in/out of stock infrequently, this might be workable. In fact, many people still send Back in Stock Campaign notifications to not just folks on the waitlist but to a broader segment as well.
