What upsell app is Makaro Jewelry using?

[NatuRise_DE]

We discovered a very nice upsell feature on the https://makarojewelry.com store and 

want to find out which upsell app they are using... Maybe someone knows which one it is or how we can realize the upsell options before the customer finishes the order? (See attached picture)

Best Regards!

[AvocadosLab]

Looking through source code this seems possible only if you have Shopify plus which allows editing checkout.liquid. This shop in particular is using Rebuy app.

[binal_identix]

They are using the https://apps.shopify.com/rebuy app in their store to show upsell products on the checkout page. There are a few other apps available in the Shopify app store to upsell products on the Checkout page and Cart page as well in the Cart Drawer.