Cart widgets

Cart popup

Checkout-trigger

The Cart Popup is the highest-intent surface in your store. It fires when the customer clicks Checkout from the cart page or drawer — they've made the buying decision, they're about to pay, and a single relevant offer at this exact moment lifts AOV more than any other widget.

Three layouts cover the three psychological angles that work at checkout-time: a single hero recommendation, a mini bundle, or a multi-select add-on list.

Layouts

Cart Cross-sell Popup

Single product

Full overlay with one recommended product and a clear Add-to-Order button. The customer can dismiss with one click and continue checkout — no pressure, no friction.

Last-chance lift before checkout — adds one click to the flow.
'Don't forget' psychology boosts CVR — the customer was already paying.
Quick dismiss keeps the checkout flow fast for shoppers who don't want it.

Expected AOV impact: 8–15% AOV lift on checkout-trigger.

Best for: Stores with a clear hero accessory or premium variant that pairs with most cart contents (warranty, gift box, premium edition).

Cart FBT Popup

Bundle

FBT-style popup at checkout time. Checkboxes for each suggested item, live total that updates as the customer ticks boxes, and a single Add button at the bottom.

Combines bundle psychology with checkout urgency.
Customer picks which add-ons they want — no all-or-nothing.
Optional automatic bundle discount applied through Shopify Functions.
Works on both the cart page and the cart drawer.

Expected AOV impact: 10–18% AOV lift on checkout-trigger.

Best for: Categories where buyers tend to forget accessories (electronics, beauty kits, kitchen sets).

Cart Add-ons Popup

Multi-select

Checkbox list of optional extras shown right before checkout. Multi-select with one Add-to-Cart click, or a Skip button to keep the checkout flow fast.

Captures add-ons that get forgotten on the PDP — gift wrap, warranty, samples.
Multi-select with one click — no individual Add buttons to fumble through.
Skip option keeps checkout fast for customers who don't want extras.

Expected AOV impact: 5–12% AOV lift on checkout-trigger, with high attach rates (15–35% of carts) on stores with relevant add-ons.

Best for: Hard goods, apparel, gift-driven categories where small extras (gift wrap, expedited shipping, warranty) are commonly forgotten.

How to create a Cart Popup campaign

In the Summer Upsell admin

1 Click + New campaign → Cart Popup.
2 Pick Cart Popup — Cross-sell, — FBT, or — Add-ons.
3 Offer name (e.g. Pre-checkout — Gift wrap).
4 Trigger: usually All Products (the popup fires for every cart-to-checkout transition) or Specific Collections for scoped offers.
5 Pick the Upsell Source and products.
6 Optional: enable discount.
7 Design tab: preset, Widget Title (e.g. One last thing), Button Text.
8 Save.

In the Shopify theme editor

1 Open Online Store → Themes → Customize.
2 Switch to the Cart template.
3 Click Add block anywhere on the cart section (position doesn't matter — the popup is a full-screen overlay).
4 Pick Summer: Cart Popup from the Apps section. (Note: this block targets body, so it intercepts the Checkout click globally for the cart page.)
5 Repeat for the Cart drawer section if your theme uses one.
6 Click Save.

Field	Type	Description
Offer name	Text	Internal label only — used to find the campaign on the dashboard. Customers never see it.
Trigger Type	Dropdown	All Products, Specific Products, or Specific Collections. Picks where the widget is eligible to render.
Trigger products / collections	Picker	Shown when the trigger type is specific. Pick the products or collections that should fire the widget.
Upsell Source	Dropdown	Manual, Basic AI, or Summer AI. See the Upsell sources page for the full breakdown.
Upsell products	Picker	Shown when source = Manual. Pick the products that the widget will recommend.
Enable discount	Toggle	Turn on to add an automatic discount to the upsell. Configures a real Shopify Function discount under the hood.
Discount Type / Value	Dropdown + number	Percentage (%) or Fixed Amount ($). Value is the percentage or money amount.
When to apply?	Dropdown	Always (on selected products) or Only when trigger product is in cart. Use the second to prevent customers from buying the upsell alone with the discount.

Design tab

Every campaign opens on the Offer tab. The Design tab next to it controls how the widget looks on the storefront. The same set of controls is reused across nearly every widget type, so once you learn it on one campaign the rest are familiar.

Field	Type	Description
Widget Title	Text	Heading shown above the widget (e.g. You may also like, Frequently bought together).
Button Text	Text	Label on every Add / Add to cart button rendered inside the widget.
Color preset	Visual picker	27 ready-made themes: Modern Clean, Ink → Slate, Slate → Ocean, Espresso → Sunset, Blossom → Crimson, Teal → Ocean, Forest → Teal, Ocean → Glacier, Sunset → Crimson, Lilac → Denim, Cherry Blossom, Piggy Pink, Fresh Mint, Baby Blue, Sand, Lavender, Honey → Amber, Vanilla → Cream, Royal → Violet, Sunset Orange, Moonlit Asteroid, Amin, Celestial, Witching Hour, Frost, Quepal and Sublime Light. Picking a preset fills every color field below at once — then fine-tune anything you want.
Font family	Dropdown	Your Theme Font (inherits from your theme), Inter, Roboto, Montserrat, Poppins, Playfair Display, Libre Baskerville, Oswald, Plus Jakarta Sans.
Title / Price / Compare / Button font size	Number (px)	Individual font sizes per element. Set Compare Price Size smaller than Price Font Size for a clean strike-through look.
Button / Title / Price / Compare colors	Color picker	Override the preset for any single element. Useful when one color needs to match a brand accent.
Border Radius	Number (px)	Rounding on product cards and CTA buttons. 0 = squared, 12–16 = soft modern, 24+ = pill-shaped.
Card Border	Color picker	Border color on each product card. Set to transparent or the same as your page background for a flat look.
Image Fit	Dropdown	Cover (crop to fill), Contain (fit inside, may show whitespace), Fill (stretch to fit).

Tip: Click any color preset to seed every color field at once, then nudge the individual swatches. Faster than building a palette from scratch.

Languages tab

If your shop runs multiple locales, the Languages tab lets you override Widget Title and Button Text per locale. Six locales ship out of the box: English, Spanish, French, Arabic, Turkish, Russian. Anything you leave blank falls back to the campaign default from the Design tab.

Trigger and frequency

Fires when the customer clicks the Checkout button on the cart page or drawer.
Show-once-per-session by default — returning customers see a fresh trigger after their session expires.

In-cart upsell

Post-purchase upsell