How to Add an Upsell Popup on Squarespace
An Upsell popup on Squarespace fires at the single most valuable moment in the buying journey — the instant a customer clicks "Add to Cart." They've just made their first buying decision. They're fully committed. Their purchase intent is at its peak. This is the best moment to show them a relevant additional offer.
Here's how to add an Upsell popup to your Squarespace store.
What an Upsell Popup Does
Instead of navigating to the cart page when a customer clicks "Add to Cart," an Upsell popup fires an offer overlay on the current page. The popup shows a relevant product suggestion — a cross-sell, a bundle, or a frequently bought together recommendation — with an option to add it to the cart before proceeding to checkout.
The customer is still on the product page. The page behind is unchanged. The popup creates a focused moment of attention for the offer before the customer moves on.
Why Upsell Popups Convert Well
The click on "Add to Cart" is the highest-intent action on the product page. The customer has just resolved their buying decision for the main product — but that decision hasn't yet closed their buying mindset. In the seconds between clicking Add to Cart and proceeding to checkout, they're open to one more relevant consideration.
A well-timed, relevant Upsell popup catches that window precisely.
Does Squarespace Support Upsell Popups Natively?
No. Squarespace has no native popup feature tied to the Add to Cart action. A plugin is required.
How to Add an Upsell Popup With UpsellGrow
UpsellGrow supports "Popup on Add to Cart" as one of the six position options for product page offers. Here's the setup:
Step 1: Create a New Offer
In the UpsellGrow dashboard, click "New Offer." Select "Product Page" as the location and choose your offer type (cross-sell is most common for Upsell popups).
Step 2: Select Trigger and Suggested Products
Choose the trigger products — the product pages where the popup will appear. Choose the products to suggest in the popup.
Step 3: Select "Popup on Add to Cart" as the Position
In the position picker, select "Popup on Add to Cart." This fires the popup when the customer clicks the Add to Cart button on any trigger product page.
Step 4: Customize the Popup Design
The popup widget is fully customizable — heading text, layout, colors, button text. UpsellGrow renders the popup with a "Just added to cart" header by default, making the context immediately clear.
Step 5: Add Conditions (Optional)
Add conditions if needed — minimum cart value, product exclusions, schedule windows. The popup fires only when all conditions are met.
Step 6: Publish
The popup goes live on all selected trigger product pages immediately.
Upsell Popup vs Inline Offer: Which Is Better?
Both have their place. The Upsell popup creates a focused moment of attention — the customer must engage with it before moving on. This means slightly higher visibility and often higher conversion for the offer. But it also adds a step to the buying flow, which can occasionally reduce checkout completion for customers who just want to get through quickly.
Test both. Many stores run an inline offer (below Add to Cart) as the primary placement and the popup as an additional position for the same offer, giving customers two chances to see the suggestion.
Ready to Start Earning More From Every Order?
UpsellGrow adds upsells, cross-sells, bundles, and frequently bought together offers to your Squarespace store — across 5 pages and 19 positions. No coding. Setup takes minutes.