Which App Is Slowing Down Your Shopify Store? How to Find It

To find which app is slowing your Shopify store, look at what each app loads on your pages rather than at your list of apps. AccessComply’s scan adds up what every outside source puts on a page, leaving out Shopify and your own domain, and names the heaviest. Shopify’s web performance report marks app installs on its timeline, so a slowdown that starts on an install date points to that app. Removing apps you no longer use is the simplest fix. The app does not remove or delay scripts for you, because that can break checkout, tracking or reviews.

How apps slow down a Shopify page

An app that does anything on your storefront adds files to it: a script, a stylesheet, fonts or images, often served from the app developer’s own servers. Google’s guide to loading third party JavaScript names the usual costs: too many network requests to several servers, and too much JavaScript keeping the browser’s main thread busy. Every extra server also needs its own connection before anything arrives from it.

On Shopify, app code reaches your pages in three ways, described in Shopify’s guide to extending your theme with apps:

• App embeds, elements that float or display as an overlay, or add code to your store without being visible to customers. Each one has a toggle in the theme editor.
• App blocks, which you place inside a section where the app’s feature should appear.
• Code in the theme itself. Some apps inject code directly into your theme’s files, and it can stay there after the app is gone.

The costliest case is a script in the page’s head without async or defer: the browser stops building the page until that script has downloaded and run. Google’s advice is to always load third party scripts with async or defer unless the script is needed for the first render.

What the scan measures on each page

AccessComply loads each page it scans in a lab browser and records every file the page downloads, where it came from and how long it took. Four findings come from that record:

The outside total counts every server that is neither your store’s domain, including its subdomains, nor one of Shopify’s own, so Shopify’s files and Shop Pay are never blamed on an app. The finding is marked serious from 1 MB. Each figure comes from one load in a desktop lab browser, so treat it as a pointer to the cause, not as what your shoppers experienced.

How the finding names the app

A list of server names does not tell you which app to look at, so the finding names them. It lists the three heaviest outside sources with what each added, and how many more there were. It recognises the apps Shopify stores commonly run: email and SMS tools, reviews, chat widgets, analytics and session recording, ad pixels, tag managers, web fonts, video players, search, cookie consent, translation and accessibility overlays. Servers that belong to the same app are added together, since you installed one app, not two servers.

A server it does not recognise appears under its own name, such as cdn.example.com. It is never guessed, because a wrong name would send you to remove the wrong app.

How to find the app behind a slow page

1. Scan the store and open the finding “Apps and scripts from outside your store are slowing this page” on your busiest pages, usually the home page and a product page. Note the names.
2. Match each name to an app in Settings, Apps. A font or a video player may come from your theme settings instead, and a pixel may have been added by an agency.
3. Check the dates. Shopify’s web performance report marks app installs, theme updates and new code on its timeline. A metric that worsened just after an install points to that app.
4. Decide what to do with each app, using the next section.
5. Scan again after each change. The total and the names are measured afresh, so you can see what the change saved.

What to do with each app you find

• Remove what you no longer use. Uninstall it from Settings, Apps. Shopify’s guide to uninstalling apps says some apps add code to your theme that is not removed automatically, and suggests checking the app’s listing or asking its developer whether extra steps are needed. Then duplicate your theme and search its code (Online Store, Themes, Edit code) for the app’s name.
• Turn off embeds for features you have stopped using. In the theme editor, the App embeds icon lists each installed app’s embeds with a toggle.
• Ask the developer about apps you keep. Ask whether its script can load with async or defer, and whether it can load only on the pages that use it, such as a reviews widget on product pages.
• Keep the pixels someone reports on. For a tag an agency added, ask whether anyone still reads its numbers.
• Settle on one font family and one video player, since each extra one is more to download.

Do not add defer to an app’s script yourself without asking its developer. Some scripts must run in a set order, and delaying one can break the feature it belongs to.

Why AccessComply reports app scripts instead of changing them

Delaying a script, inlining a stylesheet or removing an outside file can break checkout, tracking pixels, product feeds, chat and theme behaviour, and the order scripts run in can matter to the storefront. So these findings are reports: the app names what is heavy and where it came from, and the decision stays with you.

What it does change, after you approve, are image attributes it can place exactly: giving images their width and height, lazy loading images further down the page, and prioritizing the main image. Shopify page speed: what AccessComply checks and fixes covers those, and the main product image and LCP covers the image that usually decides load time.

Check the change with real visits

A lab load finds the cause; your shoppers show the result. Shopify’s web performance report shows loading speed (LCP), responsiveness to taps and clicks (INP) and layout stability (CLS) from real visits over the past 30 days. After you remove an app or turn off an embed, wait for new visits and compare the weeks before and after the change.

The speed topic collects the related guides. These checks run in every scan on every plan; see pricing.

Sources

• web.dev, Load third party JavaScript.
• Shopify Help Center, Extend your theme with apps.
• Shopify Help Center, Uninstalling apps.
• Shopify Help Center, Web performance reports.