Why your Shopify store is so slow, and how to speed it up

Shopify’s web performance reports measure the store the way Google does, with the three Core Web Vitals: how quickly the main content loads, how stable the layout is, and how quickly the page responds. They use data from real visitors. Run a product page and the home page through Google’s PageSpeed Insights as well, on the mobile tab, to see the list of what delayed each. Our guide to checking your website speed explains the measures.

The theme is the code behind every page. Shopify advises using an up-to-date, optimised theme, and says its own current themes are built for performance. An older theme, or one heavily customised over the years, carries code the store no longer uses.

Many apps add scripts to the storefront, and those scripts load on every page whether or not the page uses them. Shopify’s advice is to evaluate each app and ask whether it earns its cost in speed. Review them one by one: reviews widgets, pop-ups, chat, upsells, currency switchers.

Removing an app does not always remove what it added to the theme. After uninstalling, check the theme for leftover code, or have someone check it for you.

Tracking tags, embedded feeds and snippets pasted into the theme accumulate. Each was added for a reason that may no longer hold. List them, and remove what is no longer used.

Start with what costs most.

1. Remove apps that are not earning their place, and clear what they left in the theme.
2. Replace a slideshow or video at the top of the home page with one image.
3. Update the theme, or move to a current one.
4. Remove unused tracking tags and embeds.
5. Cut the fonts to two.

Then read the reports again. The real-visitor figures follow about a month behind the change.

A Shopify store runs on Shopify’s servers, and parts of it, including the checkout, are Shopify’s own code. Those parts are generally fast. If a store is still slow after its theme and apps have been trimmed, the remaining weight is usually in the theme’s design, and a lighter theme or a rebuilt storefront is the next step.