Why Is My Shopify Store Slow? Common Causes and Fixes

If your Shopify store is slow, the cause is usually not Shopify’s servers. In most stores, slowness comes from too many apps loading scripts, oversized images, heavy theme features such as sliders and videos, and third-party tracking code. The good news is that most of these can be fixed without rebuilding the store.

Quick Summary: Executive Takeaways

• Shopify’s hosting and CDN are rarely the bottleneck; what you add on top usually is.
• Apps are the most common cause: each one can add JavaScript to every page.
• Images are often far bigger than they need to be, especially on mobile.
• Measure with real-user data (Core Web Vitals in Search Console) as well as lab tools.
• Fix the biggest issues first: unused apps, hero images, sliders and tracking scripts.
• Speed is a trade-off: some features are worth their cost; decide deliberately.

Introduction: Why Shopify Store Speed Matters

Page speed is how quickly a page loads and becomes usable for a visitor. A slow store frustrates shoppers, especially on mobile data, and Google uses Core Web Vitals as part of its page experience signals (Google Search Central).

This guide is written by the Lazapi team, a Shopify development agency with locations in Kozhikode (Kerala), Bangalore and the UAE. When a client tells us their Shopify store is slow, the first thing we do is open the theme code and count the scripts. More often than not, there’s leftover code from apps that were uninstalled months ago.

How to Measure Shopify Speed Properly

You should measure speed with both lab tests and real-user data, because each tells you something different. A single PageSpeed score is a starting point, not the full picture.

Core Web Vitals are Google’s set of metrics for real-world user experience: loading, interactivity and visual stability.

Thresholds are from web.dev’s Core Web Vitals guide.

Edge case: small stores may not have enough traffic for field data. In that case, rely on lab tests of your main templates (home, collection, product, cart) on a mobile profile.

Common Causes of a Slow Shopify Store

These are the issues we find most often, roughly in order of how frequently they appear.

Apps and leftover code

App bloat is when installed apps add more code to your store than the features are worth. Modern Shopify “app embeds” can be switched off in the theme editor, but older apps often inserted snippets directly into theme files. In practice, finding leftovers looks like this: open the code editor and search theme.liquid for app snippets.

{%- comment -%} Example of leftover code from an uninstalled app {%- endcomment -%}
{% render 'old-reviews-app-snippet' %}
<script src="https://cdn.example-app.com/widget.js"></script>

If the app is gone, the snippet and script tag can usually be removed. Always duplicate the theme first and test on the copy.

Images

Use Shopify’s image URL filters so the browser downloads a size that matches the screen:

{{ product.featured_image | image_url: width: 800 | image_tag:
   widths: '400, 600, 800, 1200',
   sizes: '(min-width: 990px) 50vw, 100vw',
   loading: 'lazy' }}

Don’t lazy-load the main hero or first product image; it’s usually the LCP element and should load immediately.

Third-party scripts

Marketing pixels, chat widgets and review widgets all add up. Check whether two tools are doing the same job, and load non-essential widgets after the page is interactive where the tool allows it.

Theme and fonts

A theme is the code that controls your store’s layout and design, and older themes can load features on every page even when they’re not used. Shopify’s Online Store 2.0 themes, such as Dawn, are generally built with performance in mind. If your theme hasn’t been updated in years, compare it against a current version on a duplicate before investing heavily in fixing old code.

Fonts are a smaller but common issue. Each font weight is a separate file. Two weights (regular and bold) are usually enough; many stores load five or six. Shopify’s font picker serves fonts from its own CDN, which is usually faster than loading them from an external service.

Speed Trade-offs: What’s Worth Keeping

Not every slow feature should be removed. Speed is a balance between what helps customers buy and what just adds weight. In practice, we ask one question for each feature: does it help a shopper decide or buy?

Step-by-Step: How to Speed Up a Slow Shopify Store

1. Duplicate your live theme so you can test safely.
2. Measure key templates on mobile: home, collection, product and cart.
3. List every installed app and what it does; remove the ones you don’t need.
4. Search theme files for leftover app code and remove it on the duplicate.
5. Replace sliders and autoplay video above the fold with a single optimised image.
6. Fix image sizes using image_url and image_tag with responsive widths.
7. Audit tracking scripts and remove duplicates.
8. Reduce font files to the weights you really use.
9. Re-test the same templates and compare.
10. Publish the faster theme and monitor Core Web Vitals in Search Console over the next weeks.

Common Pitfalls and Mistakes to Avoid

• Installing a “speed booster” app that adds more code than it saves.
• Chasing a perfect 100 score instead of real improvements for mobile users.
• Lazy-loading the hero image, which can make LCP worse.
• Editing the live theme without a backup.
• Removing scripts without checking what they power, such as conversion tracking.
• Testing only on desktop, when most shoppers typically browse on phones.

FAQ

Why is my Shopify store slow even though Shopify hosts it?

Hosting is rarely the issue. Most slowness comes from apps, large images, heavy theme features and third-party scripts that load on top of Shopify’s platform.

Do Shopify apps slow down my store?

They can. Many apps add JavaScript or CSS to every page. Remove apps you don’t use, and check that uninstalled apps didn’t leave code behind in your theme.

What is a good PageSpeed score for Shopify?

There’s no single target. Focus on passing Core Web Vitals (LCP, INP and CLS) for real users, and on improving your key templates on mobile, rather than chasing a perfect score.

Will a faster store improve my sales?

Faster pages generally create a better shopping experience, and many retailers report better engagement after speed work. Results vary by store, so measure conversions before and after changes.

Conclusion and Next Steps

A slow Shopify store is usually fixable: measure properly, cut unused apps and leftover code, size images correctly and question every third-party script.

Next steps:

1. Run steps 1–3 above today; they often reveal the biggest wins.
2. Improve rankings alongside speed with our Shopify SEO guide.
3. Want it fixed for you? See our Shopify speed optimisation service or request a free store audit.