Why Shopify stores slow down
Shopify hosts every store on a fast, global network, so the server is rarely the problem. Stores get slow because of what is added on top over time:
- apps that add code to every page;
- theme edits, sections and sliders;
- large images and autoplaying video;
- tracking and marketing scripts.
The good news is that all of these are within your control.
Measure the right pages
Do not judge speed by the home page alone. Test four kinds of page, because each one loads different things:
- the home page;
- a collection page;
- a product page;
- the cart.
Use PageSpeed Insights (pagespeed.web.dev) on a phone setting, and look at Core Web Vitals: Largest Contentful Paint should be 2.5 seconds or less, Interaction to Next Paint 200 milliseconds or less, and Cumulative Layout Shift 0.1 or less.
Shopify also has a Web performance report in the admin, under Analytics, built from real visitors’ data. It is the best way to see whether a change helped real customers, but it takes a while to update, so use PageSpeed Insights for quick checks.
1. Apps that load on every page
This is the most common cause. Many apps add a script to every page of the store, even if you only use them on the product page or not at all any more.
- Go through your installed apps and remove the ones you no longer use.
- Uninstalling is not always enough. Older apps sometimes left code in theme files. Search your theme code for the names of apps you have removed, or ask a developer to clean it out.
- Prefer apps built on Shopify’s newer app embeds and theme app extensions, which you can switch off from the theme editor, and apps that use Shopify Functions, which run inside Shopify’s checkout and add nothing to your theme at all.
2. Big images
Shopify resizes images for you, but only if the theme asks for the right sizes. Upload images at a sensible size (around 2,000 pixels wide is plenty for a full-width banner), check that the theme serves smaller versions to phones, and make sure images below the first screen lazy load while the main image does not.
3. Sliders and autoplay video in the hero
A slideshow at the top of the home page loads several large images before a visitor sees anything, and most visitors never see past the first slide. A single strong image or a short, muted, compressed video usually converts as well and loads much faster. If you keep video, show a poster image and keep the file small.
4. An old or heavily edited theme
Themes from Shopify’s Online Store 2.0 generation are built for speed and load code only for the sections a page uses. Older themes, and themes edited many times by different people, often carry code for features nobody uses.
If your theme is several years old, moving to a current, well-built theme, or a custom one built for your products, often makes the biggest single difference.
5. Tracking and marketing scripts
Analytics, ad pixels, heatmaps, reviews, chat, pop-ups and loyalty widgets each load code from another company’s servers.
- Remove duplicates; it is common to find the same pixel added twice, once by an app and once by hand.
- Use Shopify’s customer events to manage tracking pixels in one place instead of pasting scripts into the theme.
- Delay chat and pop-up widgets until the visitor has been on the page for a moment.
6. Fonts
Every font family and weight is another download. Use the fonts in Shopify’s font library where you can, keep to two families at most, and avoid loading weights you do not use.
7. Too much on the home page
Long home pages with many sections, each pulling in products, reviews and images, are slow to load and slow to scroll. Keep the first screen focused: one clear message, one image and a way into the shop. Move secondary sections further down or onto their own pages.
What not to worry about
- Shopify’s own checkout is fast and managed by Shopify; you cannot and do not need to optimise it.
- The speed score alone. A score is a guide, not the goal. A store that loads its main content quickly and responds instantly to taps is doing well, even if the score is not perfect.
A quick checklist
- Test the home, collection, product and cart pages on a phone setting.
- Remove unused apps and the code they left behind.
- Check images are sized well and lazy loaded below the first screen.
- Replace the hero slider with one image or a short, light video.
- Review the theme’s age and how much custom code it carries.
- Clean up tracking scripts and move pixels to customer events.
- Trim fonts and home page sections.
Test after each change. If the store is still slow after the quick fixes, the theme is usually the cause, and a clean theme built for your products is the lasting fix.