Key takeaways
- Cross-selling in the cart shows complementary products (socks with shoes, case with a phone).
- Shopify’s product recommendations API powers “frequently bought together” logic automatically.
- Apps or Fudge give you control over which specific products appear and when.
- Cart cross-sells work best when the suggestion is genuinely useful - not just random products.
Cross-selling is recommending a product that complements what’s already in the cart. Done well, it’s a service to the buyer - they get something they’d have needed anyway. Done poorly, it’s noise that slows down checkout.
Why you can trust us
We’ve worked with hundreds of Shopify stores on cart optimisation and average order value growth. We also built Fudge — an AI storefront editor with a 5.0 rating on the Shopify App Store.
What is the difference between upselling and cross-selling on Shopify?
Upsell: Encouraging the buyer to choose a higher-value version of what they’re already buying. “Upgrade to the Pro model for $20 more.”
Cross-sell: Recommending a complementary product. “You’re buying running shoes - here are matching socks.”
In practice, both appear in the same places (cart, product page, post-purchase) and use similar implementation methods. The key difference is intent: upsells increase value on the same product choice; cross-sells expand the order to related categories.
How Shopify’s product recommendations work
Shopify has a built-in Product Recommendations API that powers “Frequently bought together” suggestions. It uses:
- Collaborative filtering: Products frequently purchased together by different customers
- Related products: Items with similar tags, collections, and product types
This is the same system that powers native theme recommendation toggles and many cross-sell apps. The recommendations improve over time as your store accumulates more purchase data.
Limitation: You can’t manually control which products the algorithm recommends. It’s automatic.
Option 1 - Native cart recommendations toggle
Some Shopify themes expose this natively in the cart:
Step 1. Go to Online Store > Themes > Customize.
Step 2. Navigate to the Cart page.
Step 3. In the cart section settings, look for “Product recommendations” or “You might also like”.
Step 4. Enable it and save.
This uses the Shopify product recommendations API automatically. Good for getting something live quickly with no setup cost.
Option 2 - Cross-sell apps
Apps give you manual control over cross-sell pairs and richer display options.
Frequently Bought Together - shows products based on actual purchase history. Can also set manual product pairs (“always suggest X with Y”).
LimeSpot Personalizer - AI-powered cross-sell suggestions with manual override capability.
Also Bought - cross-sell recommendations based on purchase data, similar to Amazon’s model.
Most of these apps add a section to the cart page or drawer. The visual integration with your theme varies by app.
Option 3 - Custom cross-sell section with Fudge
For cross-sells that look fully native to your store, Fudge can build a custom implementation.
Example prompts:
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“When the cart contains a product from the ‘Shoes’ collection, show a cross-sell suggestion for a product from the ‘Socks’ collection. Display one product with a thumbnail, name, price, and ‘Add’ button. Position below the cart items.”
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“Add a ‘People also buy’ section to the cart drawer showing two manually curated products. I want to specify which products appear. Style it as small cards with the product image, name, and a quick-add button.”
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“Create a cross-sell row that shows when a specific product (ID: 12345) is in the cart. Show the matching accessory from our accessories collection with an ‘Add to complete the set’ label.”
Fudge generates this as native Liquid code in your theme. Review and publish.
Cross-sell placement options
Cart drawer: Good for one or two high-relevance suggestions. Space is limited in the drawer, so be selective.
Cart page: More room for a full “Frequently Bought Together” grid. Buyers navigating to the cart page are deliberate and have more attention for suggestions.
Product page: The “Frequently Bought Together” or “Complete the Look” section below the product information is a classic cross-sell placement - before the buyer even reaches the cart.
Post-purchase: On the order confirmation page. Lower conversion but zero risk of distracting the buyer from completing their purchase.
Making cross-sells work well
Relevance is everything. Socks with shoes. A case with a phone. A cleaner with a mop. Irrelevant cross-sells get ignored and erode trust.
One clear suggestion beats many weak ones. If you have to show a grid of 8 “related products” to include anything relevant, your cross-sell data isn’t good enough yet. Start with one obvious pair.
Label the relationship. “Complete the set”, “Frequently bought with”, “Most people also add” - tell buyers why you’re suggesting it.
One-click add. Don’t make the buyer navigate to a product page to add the cross-sell. An “Add” button that goes directly to cart is the standard.
