Why Your Shopify Store Is Slow: 10 Fixes, Ranked by Impact

Shopify itself is fast: servers, CDN and image optimisation are already taken care of. Yet plenty of Shopify stores are still slow — and the cause is almost never the platform. It's what's been added on top: apps, scripts, heavy images and sliders.

Here are the 10 fixes that make the biggest difference, ranked by impact — from most important to nice-to-have.

Measure first

Google judges speed by three Core Web Vitals, measured on real visitors (75th percentile, mobile):

Metric	What it measures	"Good"
LCP	How quickly the main content appears	under 2.5 s
INP	How quickly the page responds to input	under 200 ms
CLS	Whether the layout jumps while loading	under 0.1

Where to look:

1. Shopify: Online Store → Themes. The web performance dashboard shows real visitor data — LCP, INP and CLS by page type and device.
2. Google Search Console → Core Web Vitals — what Google itself sees.
3. PageSpeed Insights — to diagnose a specific page.

In practice, most Shopify stores that fail Core Web Vitals fail on LCP — which is why the first fixes focus on it.

10 fixes, ranked by impact

#	Fix	Improves	Effort
1	Audit your apps	LCP, INP	Low
2	Hero image	LCP	Low
3	Drop the hero slider and autoplay video	LCP, CLS	Low
4	Defer third-party scripts	INP, LCP	Medium
5	Lazy-load other images	LCP	Low
6	Fonts	LCP, CLS	Low
7	Reserve space for banners	CLS	Low
8	Unused theme JS and CSS	INP, LCP	Medium
9	Collection pages	LCP, INP	Medium
10	Slow Liquid	LCP	High

1. Audit your apps

Each app can load its own scripts, styles and widgets on every page — even where it isn't needed. The number of installed apps is one of the strongest predictors of a slow store.

1. List every app and ask of each one: does it make money or save time?
2. Uninstall the ones you don't use.
3. Check for leftover code. Older apps often inserted code directly into the theme, and it stays after uninstalling. Look for remnants in theme.liquid and the snippets folder.
4. Turn off app embeds in the theme editor wherever they aren't needed.

2. Optimise the hero image

The main image above the fold is usually your LCP element. Three rules:

• The right size. Don't send a 4000 px image to a phone — Shopify generates the sizes you ask for.
• Never lazy-load it. loading="lazy" above the fold delays exactly the element that should appear first.
• High priority with fetchpriority="high".

{{ section.settings.image
  | image_url: width: 1600
  | image_tag:
    widths: '400, 800, 1200, 1600',
    sizes: '100vw',
    loading: 'eager',
    fetchpriority: 'high' }}

3. Drop the hero slider and autoplay video

A hero slider means several large images plus JavaScript to rotate them, and shoppers rarely look past the first slide. A static image with a clear headline and button is almost always faster — and often sells better.

If video matters to your brand, show a poster image and load the video only on click.

4. Defer third-party scripts

Live chat, review widgets, pop-ups, trackers — every script competes for the phone's resources, and they're the most common cause of poor INP.

• Load chat on interaction: show the button, and load the widget itself after a click or a few seconds' delay.
• Add analytics pixels through Shopify's Customer events rather than pasting them into theme code.
• Load the review widget on product pages when the shopper scrolls to it.

5. Lazy-load everything else

Everything below the fold — product images, banners, logos — should be lazy-loaded (loading="lazy"), so the browser fetches what the shopper can see right now first.

6. Tidy up your fonts

• At most two font families, and only the weights you actually use.
• font-display: swap — text shows immediately in a system font, and your brand font swaps in once loaded.
• System fonts for body text are the fastest option there is.

7. Reserve space for banners and widgets

An announcement bar, cookie banner or app widget that appears late pushes the whole page down — hurting CLS and annoying shoppers.

• Set width and height on every image.
• Reserve space for elements that load later (a minimum height on the block).
• Show pop-ups on top of the page rather than inserting them into the layout.

8. Strip unused JavaScript and CSS from the theme

Older themes often ship jQuery, several animation libraries and styles for sections you removed long ago. If your theme is dated, moving to a modern Online Store 2.0 theme can do more than dozens of small tweaks.

9. Optimise collection pages

• A sensible number of products per page — pagination or "Load more" beats 100 cards at once.
• Be careful with quick-view and swatches that load data for every card.
• Load the hover image only when it's needed.

10. Speed up slow Liquid

If the server takes a long time to return the page before any images even start loading, the problem is the theme code: nested loops, iterating over every product in a collection, duplicated logic. The Shopify Theme Inspector for Chrome extension helps find the slow spots. This is the hardest fix — and the one you'll need least often.

Checklist

1. Measured LCP, INP and CLS in the Shopify dashboard and Search Console.
2. Removed unused apps and their leftover code.
3. Optimised the hero image: size, no lazy-loading, high priority.
4. Replaced the slider with a static hero.
5. Deferred chat, widgets and trackers.
6. Checked fonts, image dimensions and space for banners.
7. Measured again after 2–4 weeks — field data takes time to update.