Shopify Speed Optimization: The Checklist I Run on Every Slow Store
Kyle Andes
A slow Shopify store loses sales before anyone sees your products: roughly half of mobile visitors abandon pages that take more than three seconds to load, and most slow Shopify stores I audit have the same four or five problems. This is the checklist I run as a freelance Shopify developer when a store owner tells me "my site feels slow," in the order I run it, including the parts you can do yourself for free.
First, measure the right thing
Before touching anything, get a real baseline. Two tools, both free:
- PageSpeed Insights (pagespeed.web.dev): enter your store URL, look at the mobile score and the Core Web Vitals section. Ignore the desktop score; your customers are on phones.
- Your own phone on mobile data: open your store in an incognito tab, off wifi. This is what your actual customer experiences, and it's regularly worse than any tool reports.
Write down three numbers: LCP (how long until the main content shows), your mobile performance score, and how long the product page takes on your phone. Everything below is about moving those.
One honest caveat: Lighthouse scores are a diagnostic, not the goal. I've seen stores score 55 and feel fast, and stores score 75 and feel broken. Optimize for the customer experience, use the score to track direction.
The checklist, in order of impact
1. Audit your apps (the biggest win, almost every time)
Every Shopify app you install can inject scripts into your storefront, and they keep injecting them even after you stop using the app, sometimes even after you uninstall it.
Do this today:
- List your installed apps. For each one, ask: did this earn its keep last month?
- Uninstall anything you're not actively using.
- In your theme editor, check App embeds (Theme settings) and turn off embeds for apps you don't use on the storefront.
- If you're technical, view your page source and count third-party scripts. More than a dozen is a red flag.
Stores routinely carry 15+ apps where 6 would do. Reviews, upsells, popups, chat, tracking pixels: each one is a tax on every page load. This step alone has taken stores I've worked on from "feels broken on mobile" to "acceptable" before I wrote a line of code.
2. Fix your images
The second most common problem, and mostly free to fix:
- Let Shopify serve responsive images. If your theme is OS 2.0 and reasonably modern, it already does this. If your theme is from 2019, this is one of many reasons to update. I've written about when a theme is worth replacing in Shopify template vs custom theme.
- Stop uploading 5MB PNGs. Product photos should be JPG or WebP. Shopify converts formats on its CDN, but oversized source files still hurt.
- Lazy-load below-the-fold images. Standard in good themes; verify by checking that offscreen images have
loading="lazy". - One good hero image beats a carousel. Sliders load multiple large images to show one, and almost nobody clicks past the first slide anyway.
3. Cut the homepage down
The homepage tries to do too much on most stores: hero video, three carousels, an Instagram feed, a review widget, a popup, and a chat bubble, all fighting for bandwidth in the first second.
Pick the one thing you want a first-time visitor to do, build the page around it, and move the rest down or out. Fewer sections isn't just a design preference; it's directly measurable in load time.
4. Check your fonts
Two custom font families maximum: one for headings, one for body, ideally in WOFF2 format. Every extra font weight is another file blocking text render. If your theme loads five weights of a display font to use two, that's free speed sitting on the table.
5. Tame the tracking pixels
Meta, TikTok, Google, Pinterest, Hotjar, Klaviyo: each pixel is a script, and they add up. Keep the ones tied to channels you actually run ads on. If you're on Shopify's higher plans, move what you can into Customer Events (server-side or sandboxed pixels) instead of raw theme scripts.
6. The theme itself (where a developer earns their fee)
If you've done all of the above and mobile still drags, the remaining weight is usually in the theme's own code: render-blocking scripts, layout shifts from ads-style banners, unoptimized Liquid loops on collection pages, or a page-builder app wrapping your whole storefront in its own runtime.
This is the point where it makes sense to bring in a developer rather than install a "speed booster" app. Speed apps mostly apply the free fixes above (and add their own script in the process). A developer removes weight; an app adds a layer that hides it.
Typical developer-level work: deferring non-critical JavaScript, inlining critical CSS, replacing heavy app widgets with native theme sections, cleaning up leftover code from uninstalled apps, and restructuring the product page so the buy box renders first.
What NOT to spend money on
- "Speed optimization" apps that promise instant 90+ scores. Some literally lazy-load your entire page to game Lighthouse while making the real experience worse.
- Upgrading Shopify plans for speed. Your plan doesn't change storefront rendering speed.
- A full redesign when the problem is 12 apps. Run the checklist first. If someone quotes you a rebuild without auditing your apps, get a second opinion. I've broken down what rebuilds actually cost in How much does a custom Shopify theme cost in 2026?
What results look like
On a recent apparel store project, the app audit plus image fixes plus theme-level script deferral cut page load time by roughly 40 percent and made the mobile checkout flow noticeably snappier.
The pattern holds across most stores: the first 60 percent of improvement comes from removing things, not adding them.
FAQ
What's a good PageSpeed score for a Shopify store? Mobile 50+ is workable, 70+ is good for a store with real apps and tracking. Chasing 95+ on Shopify usually costs more than it returns.
Can I do this without a developer? Steps 1 through 5, yes, this weekend. Step 6 needs someone comfortable in Liquid and JavaScript.
How much does professional speed optimization cost? As a fixed-scope project, typically $500 to $2,000 depending on how deep the theme problems go, and it usually pays for itself out of recovered mobile conversions.
Does site speed affect Google rankings? Yes. Core Web Vitals are a confirmed ranking signal, and speed compounds: faster pages get crawled more, convert better, and earn more links.
Ran the checklist and still stuck? Book a discovery call and bring your PageSpeed numbers. I'll tell you within 30 minutes whether it's an app problem, an image problem, or a theme problem.
Kyle Andes
Full-stack developer and designer crafting modern digital experiences. Passionate about clean code, thoughtful UI, and building products that leave a lasting impression.
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