November 1, 2026
Enable sticky add to cart on product pages long enough that the buy button scrolls out of view, place it at the bottom on mobile, and make sure it shows price and variant, not just a button. Test it against your announcement bar and cookie banner for overlap. On short product pages it adds nothing and should stay off.
There is a specific mobile session this feature exists for. The buyer has scrolled through photos, a sizing table, and a long description on their phone, they are convinced, and the buy button is four screens behind them. Every store has watched that session end in an exit in their recordings and felt it.
A sticky bar fixes that one moment. It also creates three new problems when it is set up lazily: it covers content, it fights the cookie banner for the same strip of screen, and it offers the wrong variant because nobody wired the selector through. Setup is easy. Setup that does not embarrass you takes an extra twenty minutes.
Sticky add to cart earns its space on long pages: apparel with sizing content, supplements with ingredient detail, furniture with dimensions and care. On a short page where the buy button is visible within one scroll, a sticky bar is pure clutter competing with your actual button. Check your template lengths before enabling anything storewide.
Many current themes include a sticky buy section or a quick buy drawer natively. Use the native version first and check two behaviors: does the bar appear only after the main buy button scrolls away, and does it disappear near the footer and reviews instead of camping on the screen forever. A bar that is always present trains buyers to ignore it, which defeats the entire point.
The sticky bar must reflect the selected variant and its price in real time. The classic failure is a bar hardcoded to the default variant, so the buyer picks a size, scrolls, taps the sticky button, and gets the wrong size in the cart. That is not a conversion feature, it is a returns generator with extra steps. Change every variant option and confirm the bar follows before you call it done.
Sold out and preorder states need the same check. If the main button says sold out, the sticky bar cannot quietly say add to cart. Test the ugly cases: an out of stock variant, a preorder variant, and a product with a quantity selector your regulars actually use for multi buys.
On mobile, bottom placement wins because thumbs live there, but bottom is also where cookie banners, chat widgets, and announcement prompts want to be. Stack the page with everything enabled at once, on a real phone, and look at how much product is actually visible. If the answer is a letterbox, something leaves, and it should be the least revenue critical widget, not the buy button.
Judge it on add to cart rate for long page products over a few weeks, split by device, against the same period with it off if your traffic allows. Do not judge it on clicks on the sticky bar itself; a bar everyone taps because the real button is badly placed is reporting a different bug. Fix placement first, then let the sticky bar do the rescue work it is actually for.
Related reading: Add a Backorder Notice on a Shopify Product Page That Buyers Actually Read, How to Add Recently Viewed Products to a Shopify Store, and How to Add a Size Chart to a Shopify Product Page.
It can on long product pages, mainly on mobile, by removing scroll back friction at the decision moment. On short pages it typically does nothing measurable. Treat any universal lift claim with suspicion; the effect depends on page length and where your buy button sits.
Bottom, in most store layouts. It sits within thumb reach and does not compete with the header, search, and cart icons at the top. Whichever you choose, check it does not cover price information, the chat button, or the cookie banner on smaller screens.
Yes, but the bar has to carry the purchase type selection, one time versus subscription, or default honestly to the option the buyer already chose in the main section. A sticky bar that silently resets a subscription choice to one time purchase will create billing complaints.
Check the app options carefully for script weight and variant syncing, or use a quick buy drawer pattern instead. Avoid stacking a sticky bar app on top of a theme that already has a sticky header with cart elements; the combined height eats the mobile viewport.