Shopify Upsell By Email is a shopping app that helps Shopify merchants increase their sales and retain existing customers sans resorting to conventional upsell methods. In other words, you can upsell through email. This means upselling still remains a possibility with customers who have completed their purchase. Thanks to the various email customisation tools available, you can take your email game to another level. The tool integrates with all Bigcommerce and Shopify platforms. The best part is that the tool can be downloaded for free on the Shopify store.