Shopify runs on genuinely fast infrastructure. When a Shopify store is slow, and plenty are, the cause is almost never Shopify. It is what has been added on top over two years of solving problems one app at a time.
Here is how to find the real cause rather than guessing.
Ignore the speed score
Shopify shows a speed score in the admin, and store owners fixate on it. It is a single number averaged across a sample of pages and it moves for reasons that have nothing to do with your customers.
Test your actual product page in PageSpeed Insights, on mobile, and read the two numbers underneath the score. Largest Contentful Paint tells you when the main content appeared. Interaction to Next Paint tells you how quickly the page responds when someone taps. Those correspond to what a customer experiences. The score does not.
Apps are usually the answer
Every app you install adds JavaScript that has to download and run before the page settles. Individually each one seemed worth it. Collectively they are why your product page takes six seconds.
The worse problem is that uninstalling an app often does not remove its code. Many apps inject snippets directly into your theme, and removing the app leaves the snippet behind, still loading, still slowing things down, no longer doing anything at all.
Go through your installed apps and be ruthless about what is actually earning its place. Then look in your theme files for leftovers from apps you removed months ago. On most stores that have been running a few years, there are several.
Images, as always
Shopify serves images well if you let it. The problems come from what gets uploaded.
A product photograph exported at 3000 pixels wide to display at 600 is downloading five times the data needed. Shopify will resize it, but only if the theme requests the right size, and plenty of themes request the original.
Two things fix most of this. Upload at roughly twice the largest display size and no more. And check that your theme is using Shopify's image sizing rather than the raw file, which is a quick look at the markup.
The hero slider
If your homepage opens with a rotating carousel, it is costing you money in two directions.
It is slow, because it loads several large images and a JavaScript library before anything is visible. It also performs badly, because visitors overwhelmingly interact with the first slide and rarely wait for the rest. You are paying a performance penalty to show content almost nobody sees.
A single strong image with one clear call to action loads faster and converts better. This is one of the few changes that is both easier and more effective.
Themes built to demo, not to run
Marketplace themes are built to look impressive in a preview, which means they ship with every feature anyone might want: sliders, animation libraries, mega menus, quick view modals, countdown timers. You inherit the weight of all of it whether you use it or not.
This is the expensive problem, because it usually cannot be tuned away. If you have removed the apps, fixed the images, dropped the slider and the store is still slow, the theme is the answer. That is a rebuild rather than an optimisation, which is why it is worth checking last and being honest when you get there. See how we build Shopify stores.
The order that saves the most time
- Audit apps, remove what you do not use, and hunt the leftover snippets.
- Fix oversized images on your highest traffic product pages.
- Replace the carousel with one image.
- Check your theme is requesting properly sized images.
- Only then consider replacing the theme.
The first three are usually a day of work and frequently halve load time. Doing them first also means that if you do end up rebuilding, you rebuild knowing what actually mattered.
See how we work with US businesses, or send us your store URL and we will tell you which of these is costing you most.
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