Tandem

The Shopify-native upsell platform for upgrades, swaps, bundles, and subscription-aware merchandising.

• Genuine upgrades. Swap a cart line to a better product while keeping quantity, properties, and selling plans.
• One system. Add-ons, gifts, progress bars, and post-purchase offers without stacking Rebuy plus smaller apps.
• Shopify-native. Theme app extension, Discount Function, and Supabase for campaigns, analytics, and tenant isolation.