Subscription revenue grows when existing customers spend more per order. Upsell products let you surface relevant items — a one-time add-on, a complementary product, or a seasonal limited-edition — directly inside the customer portal so customers can add them to their next order as one-time add-ons, without creating a separate order. You can also promote products with the upsell block in your subscription emails. Checkout and cart upsell blocks are not available right now.
Shopify's <a href="https://shopify.dev/docs/apps/build/purchase-options/subscriptions/billing-cycles/manage-billing-cycle-contracts" target="_blank" rel="noopener">Billing Cycles API</a> supports per-cycle edits, meaning items can be added to a single upcoming order without modifying the underlying subscription contract. subZwallet uses this capability to power a merchant-controlled upsell catalog that subscribers browse from their self-service portal.
Upsells work for three common scenarios. Match each scenario to the right product selection to keep offers relevant and conversion rates high.
Rotate your upsell catalog regularly. Stale offers get ignored; fresh, relevant products drive incremental revenue.

Subscribers manage their subscription in the customer portal, which they open through their customer account or a secure link the store sends. When a subscriber views their upcoming order, active upsell products appear as add-ons. Out-of-stock products are hidden automatically.
Because upsells attach to a single billing cycle, the subscriber's base subscription is never altered. This is handled through Shopify's <a href="https://shopify.dev/docs/apps/build/purchase-options/subscriptions/billing-cycles/manage-billing-cycle-contracts" target="_blank" rel="noopener">billing cycle contract management</a>, which isolates per-cycle changes from the recurring contract.
Offering every product in your catalog as an upsell dilutes attention. Curate a focused list of 3-8 items and rotate based on season, inventory, or customer feedback. Add the upsell block to your subscription emails (for example the upcoming-order reminder) so subscribers see the add-ons before their next order, not only when they open the portal.
Track which upsell items get added most often and which get ignored. Drop underperformers after 2-3 billing cycles and replace them with new options.