Glossary

Upsell, cross-sell, FBT, bundle — these terms get thrown around interchangeably across the e-commerce industry. Inside Summer Upsell, each one has a specific meaning and a specific surface where it lives. This page maps the standard industry definitions to how they're actually used inside the app.

Funnel terminology

Upsell

Standard definition: encouraging a customer to buy a more expensive variant, upgrade, or premium edition of the product they're considering — e.g. offering a 256GB phone when they viewed the 128GB version.

In Summer Upsell: the term upsell is used loosely as the umbrella name for "any post-PDP product recommendation," which technically includes cross-sells. The specific places it appears:

• Upsell widget (PDP) — Grid / Stack / Carousel layouts. In practice usually a cross-sell. Pure upsells (premium variants of the same product) are configured by manually picking a higher-tier variant as the upsell product.
• In-Cart Upsell (cart drawer / page) — recommendations rendered inline inside the cart. Typically cross-sells, but can be configured as same-category upgrades.
• Popup Upsell (after Add-to-Cart) — modal that fires from a successful Add-to-Cart event on the PDP.
• Post-Purchase Upsell (thank-you page) — one-click offers added to the existing order.

Cross-sell

Standard definition: recommending a related or complementary product — e.g. a phone case when the customer is buying a phone. The cross-sell adds a different SKU; the upsell upgrades the same SKU.

In Summer Upsell:

• "Cross-sell" as a layout name — used inside both the Popup Upsell and Cart Popup widgets to mean a single-product recommendation card. The "Cross-sell Popup" layout shows one product at a time with one Add button.
• "Cross-sell" as a behavior — most of the recommendations shown by the Upsell widget, In-Cart Upsell, and FBT are technically cross-sells, even though the app calls the parent widget "Upsell."

If you want a true upsell (premium variant of the same SKU), use the Upsell widget with manual product picks pointing at higher-tier variants of the trigger product.

FBT (Frequently Bought Together)

Standard definition: a bundled cross-sell pattern that pairs the trigger product with multiple related items in a single Add-to-Cart action. Popularized by Amazon's "Frequently Bought Together" widget.

In Summer Upsell:

• FBT widget — a dedicated widget on the PDP with three layouts: Full-Width carousel, Amazon-style strip, and Classic checklist.
• FBT Popup layout — the same FBT pattern shown as a modal after Add-to-Cart (Popup Upsell widget) or before Checkout (Cart Popup widget).
• FBT discount — an all-or-nothing percentage or fixed discount applied via Shopify Functions when all required bundle items are in cart.

FBT and cross-sell overlap conceptually, but FBT specifically implies multiple products bundled together, while cross-sell typically means one recommended product at a time.

Bundle

Standard definition: a fixed-content kit or set sold as a single unit, often at a discount versus the sum of its parts.

In Summer Upsell:

• Bundle campaign type — a campaign type that uses the Amazon FBT layout for fixed-content bundles where the merchant defines the exact contents and discount.
• Bundle FBT theme block — the storefront block that renders Bundle campaigns on PDPs.

The line between an FBT bundle (selectable) and a Bundle (fixed) is enforced by the layout: Classic and Full-Width FBT let the customer toggle items, while Amazon-style Bundle FBT adds the entire kit as one click.

Add-on

Standard definition: a small-ticket complementary item — warranty, gift wrap, expedited shipping, samples — typically chosen with checkboxes rather than a "view product" flow.

In Summer Upsell:

• Add-ons Popup layout — used inside both Popup Upsell (after Add-to-Cart) and Cart Popup (before Checkout). Multi-select checkboxes, single Add button.

Funnel placement terminology

PDP (Product Detail Page)

The product page itself — the Shopify URL /products/<handle>. Three Summer Upsell widgets fire here: Upsell, FBT, and Popup Upsell.

Cart

Either the cart drawer (most modern OS 2.0 themes) or the dedicated /cart page. Two Summer Upsell widgets target this surface: In-Cart Upsell (always-visible inline) and Cart Popup (overlay on Checkout click).

Post-purchase

The Shopify thank-you / order status page shown immediately after a successful checkout. The Post-Purchase widget runs here in either Block mode (theme app block) or Custom mode (Checkout Extensibility, Shopify Plus only).

Widget mechanics

Trigger product

The product on whose page (or whose presence in the cart) a campaign should fire. Configured in the campaign builder via "All products," "Specific products," or "Specific collections."

Upsell product

The product(s) that the widget recommends when triggered. Comes from one of three sources: Manual, Basic AI, or Summer AI.

Trigger modes

For modal widgets, the event that opens the modal:

• Add-to-cart trigger — fires immediately after a successful Add-to-Cart event on the PDP. Used by the Popup Upsell widget.
• Checkout trigger — fires when the customer clicks the Checkout button on the cart page or drawer. Used by the Cart Popup widget.

Frequency cap

Show-once-per-session logic that prevents the same popup from firing twice for the same shopper. Sessions reset after 30 minutes of inactivity, matching Shopify's default session window.

Discount apply mode

• always — the discount applies whenever the upsell product ends up in the cart, regardless of what triggered it.
• trigger_in_cart — the discount applies only if the original trigger product is also in the cart at checkout. Prevents customers from gaming the offer by adding the upsell alone.

Recommendation sources

Manual

The merchant hand-picks the upsell products in the campaign builder. Best for premium SKUs, curated bundles, or any case where brand consistency matters more than relevance scoring.

Basic AI

Rule-based recommendations powered by your Shopify catalog (collections + tags + product types). Two flavors: Related (same collection / shared tags) and Complementary (frequently co-purchased collections). No credits consumed.

Summer AI (powered by ChatGPT)

LLM-driven recommendations that read product titles, descriptions, vendor, and tags to surface contextually relevant cross-sells. One credit per query. Allowance: 20/mo on Starter Pro, 1,000/mo on Pro.

Metrics

AOV (Average Order Value)

Total revenue ÷ total orders. The headline metric every upsell widget tries to lift. A $5 bump on $50 orders = 10% AOV lift, which compounds into meaningful revenue at scale. Summer Upsell tracks AOV with-vs-without the widget firing in the analytics dashboard (paid plans).

CVR (Conversion Rate)

Orders ÷ sessions. The percentage of visitors who buy. Upsell widgets generally don't affect CVR directly — they affect AOV. (A poorly placed popup can hurt CVR; a well-placed one is invisible to the metric.)

Acceptance rate

Conversions ÷ impressions for a specific widget. The % of visitors who saw the widget and added the recommended product. Different from CVR — acceptance rate is a per-widget metric.

Impressions

Number of times the widget rendered on a storefront page. Counted client-side once the widget enters the viewport.

Conversions

Orders that included an item added through the widget. Recorded server-side via the orders/paid webhook for accuracy.

Storefront integration

App embed

The Shopify theme app extension that loads summer-widgets.js in the page head. Required for any widget to render. Enabled via the theme editor's App embeds sidebar.

Theme app block

A per-widget Shopify theme block (e.g. Summer: FBT Bundle) that the merchant adds to a template through the theme editor. The block tells Shopify where the widget renders; the campaign in the admin tells Summer Upsell what to render.

App proxy

A Shopify-signed URL path (/apps/pars-upsell) that lets the storefront fetch campaign data from Summer Upsell's backend without breaking the customer's session or hitting CORS issues.

Shopify Functions

Shopify's server-side discount engine. Summer Upsell uses Functions to apply percentage and fixed discounts at checkout. Functions discounts are real Shopify discounts — they show up in the merchant's Discounts admin and flow through to receipts and reports.

Plan-specific terminology

Auto-rotate

Pro-only feature that automatically rotates campaigns flagged as non-performing (low conversion-per-impression) so they cycle out for fresh ones. Useful for stores running many simultaneous campaigns.

Auto-upgrade

The system that detects when a shop's monthly order count exceeds the current plan's limit and presents a Shopify-hosted upgrade flow on the next admin visit. Doesn't charge without merchant approval.

Summer AI credits

Internal name: Ozzy AI credits. 1 credit = 1 LLM-powered recommendation query. Cached per campaign — re-running the AI on the same campaign uses 1 fresh credit. Allowance: 20/mo on Starter Pro, 1,000/mo on Pro. Reset on the billing anniversary, not the calendar month.