Hey, no worries! I can understand how frustrating it can be when an app you've been relying on falls short. Let's see if we can find a good alternative for you.

There are quite a few cart upsell apps on Shopify that claim to work with discount codes. Here are a few that you could check out:

• Cartix Cart Discount + Upsell: This app not only offers cart upsells but also applies discount codes right in the cart.

• Free Gifts BOGO Cart Upsell: This app from Sortecom seems to be highly rated and offers various upsell and discount features.

• Selleasy - Upsell and Cross sell: Selleasy claims to work with Shopify's native discount code system and...

So I tried all of these. Sell easy was the best for setup but the widget are just terrible looking. They look like a graph and are very unappealing. I also looked into 3 other apps not on this list. None work. Am I going absolutely crazy? Why would these apps take away the ability for the seller to offer discount codes to customers via email/sms?? If I have a new email subscriber for example, I could include a shopify discount code for their next purchase that improves return rate. Also I might want to start a loyalty program that would promote brand awareness and loyalty but i can’t offer a discount code in the email?? This is madness. So I am still on the hunt for an app that can offer cart discounts for multiple items sold AND a shopify discount code can be stacked on top of those cart discounts. Very frustrating.

@SarahZ 

Any luck with your search i think this one looks pretty nice and clean and it works with discount codes: Cartix Cart Discount + Upsell 

Can you describe how you want to use cart upsell / cross sell codes in klaviyo as it seems interesting?