Product add-on

PDP

The Product Add-on widget renders inline on the product page and is purpose-built for low-friction extras the shopper would otherwise forget — warranty, gift wrap, samples, engraving. It shows the current product on top under a Customize your order heading, the add-ons below it, and its own Add button with the running total that adds the product plus every ticked add-on in one go.

Layouts

Product add-ons rendered as a compact checkbox list

Addon List

Default

Compact rows — checkbox, title and price per add-on. Nothing is pre-selected; the shopper ticks what they want and the Add button total updates.

All add-ons visible at once — no decision hidden behind a click.
The most compact of the three layouts.
The discount, if enabled, applies to the add-ons only — never to the main product.

Best for: Apparel (gift wrap, gift card), electronics (warranty), beauty (samples).

Product add-ons rendered as rows with thumbnails and an 'Optional add-on' caption

Addon Card

Visual

Roomier rows with a thumbnail, title, an Optional add-on caption and the price, each with a checkbox. Image Fit applies to this layout.

Shoppers can see what the add-on looks like.
Easier to communicate value when the add-on is visual rather than a service.

Best for: Jewelry (gift box), beauty (sample sets), home goods (matching accessories).

Product add-ons rendered as service-style toggle switches

Addon Toggle

Compact

One row per add-on with an on/off switch instead of a checkbox. Reads like a settings list.

Familiar switch pattern — single tap to enable or disable.
Good for service-style extras that don't need an image.

Best for: Warranty, gift wrap, express handling and other service add-ons.

How to create a Product Add-on campaign

In the Summer Upsell admin

1 Click Create Campaign.
2 Under Product Add-on on the Product Page list, pick List layout, Card layout or Toggle layout.
3 Offer name + Trigger (Specific products / Specific collections work best — add-ons should feel relevant).
4 Pick the add-on products (or use Automated recommendations / Summer AI). Each add-on is a real Shopify product — gift wrap, warranty etc. should already exist as products.
5 Optional: tick Enable discount for add-on products and set the display title, type and value.
6 Design tab: layout, template, Subtitle, typography.
7 Language tab: Widget Title (default Frequently added extras), Button Text, translations.
8 Click Publish. The Test campaign in store checklist runs (campaign active, products available, app embed enabled, widget block added) — fix anything red, then click Publish campaign.

In the Shopify theme editor

1 Open Online Store → Themes → Customize.
2 Switch to the Products → Default product template.
3 Click Add block near the buy button (Product Add-on widgets convert best when they're directly next to Add to cart).
4 Pick ✨ Summer: Product Add-on from the Apps section.
5 Drag to position.
6 Click Save.

Field	Type	Description
Offer name	Text	Internal label only — used to find the campaign in the admin. Customers never see it.
Trigger	Radio	All products, Specific products (default) or Specific collections. Decides where the widget is eligible to render. Cart widgets use Any cart and Post-Purchase uses Any order instead of All products.
Trigger products / collections	Picker	Shown for the Specific options. Pick the products or collections that should fire the widget.
Product source	Radio	Specific products, Automated recommendations or Summer AI powered by ChatGPT (credit-based; every plan includes credits). See Upsell sources.
Offer products	Picker	Shown when Specific products is selected — click Add Products and pick the products the widget will recommend.
Discounts	Dropdown	No discount, Use Summer Upsell discount functions (Recommended), Use discounts that are dynamically created or Use an already existing discount code. See Discounts for how each mode works.
Type / Value	Dropdown + number	Product discount (each offer item) or Order discount (the whole order), and the amount as % or a fixed amount in your store currency.
Discount code	Text	Optional for Summer discount functions (creates a code-based discount the widget applies automatically); required for existing discount code.
Combination	Checkboxes	Whether the discount can combine with product, order and shipping discounts.

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. A live preview on the right updates as you change settings — switch it between desktop, mobile and full size.

Field	Type	Description
Layout	Dropdown	Shown on widgets that have more than one layout (Cross-sell, Upsell, In-Cart Upsell, Product Add-on). Switches the layout without recreating the campaign.
Widget Title / Button Text	Text	Heading shown above the widget and the label on its Add buttons. For Classic FBT, Bundle, Popup, In-Cart Upsell, Cart Popup and Post-Purchase you set them here; for Upsell, Cross-sell, FBT Full Width and Product Add-on they live on the Language tab (default language block).
Subtitle	Text	Optional line under the title (e.g. Customers also bought these).
Templates	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 template sets the button style, card border and every color below at once — then fine-tune anything you want.
Background (optional)	Toggle + color	Give the widget its own background color instead of inheriting the page background.
Border Radius	Dropdown	Sharp (Square) or Curvy (Rounded) corners on cards and buttons.
Image Fit	Dropdown	Cover (crop to fill), Contain (fit inside, may show whitespace), Fill (stretch to fit).
Font family	Dropdown	Your Theme Font (inherits from your theme), Inter, Roboto, Montserrat, Poppins, Playfair Display, Libre Baskerville, Oswald, Plus Jakarta Sans.
Typography sizes	Number (px)	Title weight, Button font size, and individual sizes for Product Title, Price and Compare price. Set the compare size smaller than the price size for a clean strike-through look.
Colors	Color picker	Primary color, Product Title color, Price color and Compare price color. Override any single value after picking a template.

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

Language tab

The Language tab holds the storefront copy for the widget. The Default language block is always there; click Add another language to add any locale your Shopify store has published and translate the title, button text and other storefront strings for it. Default text is pre-filled in English, Spanish, French, Arabic, Turkish and German. A locale you don't add falls back to the default language.

Tip: Create your add-on products as real Shopify products with inventory tracking off — warranties, gift wrap, samples, etc. They appear in your admin like normal products but never deduct from physical stock.

Popup upsell

In-cart upsell