Mid-market Shopify store owners struggle to raise average order value at the single moment where intent is highest: checkout. Static upsell widgets feel bolted on, and generic chatbots like Chatbase are built for support Q and A rather than conversion inside a cart. The named product, Checkout Upsell Builder, embeds a product-recommendation chatbot directly into the Shopify checkout flow. Instead of a support agent, the bot acts as a contextual sales assistant that reads the cart contents and suggests complementary products with a one click add path. The solution centers on three moves: read cart context, recommend the right add on, and make purchase frictionless without leaving checkout. The MVP is a Shopify app that injects a chatbot into the checkout page, ships with a few rule based recommendation templates (frequently bought together, threshold to free shipping, accessory pairings), and reports incremental AOV lift so the value is legible to the merchant. Revenue is a monthly SaaS subscription tiered by store order volume, with a natural expansion path to performance based pricing tied to captured upsell revenue. Go to market starts inside the exact communities already teaching this pattern by hand: the ManyChat and Panda checkout tutorial audiences on YouTube who are stitching together one click upsell and instant purchase flows manually. A packaged app that does what those Part 5 and Part 6 tutorials teach removes the assembly work. Growth loops come from the Shopify App Store listing plus a merchant facing badge and case study engine: stores that see measurable AOV lift become referenceable proof, feeding App Store reviews and community word of mouth back into the top of funnel.