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Shopify Speed Optimization: Kazari Store from 25 to 95

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How We Took a Shopify Store from 25 to 95 in PageSpeed Score (and 32 to 97 on Desktop)

Speed is the new currency in eCommerce. Customers expect pages to load in seconds, not slowly reveal content while scripts, apps, and images fight for attention in the background.
Recently at Seven Nodes, we worked with Kazari – a modern jewellery brand running on Shopify – to solve exactly this problem. Their store looked great, but performance metrics were holding them back:
  • Mobile PageSpeed Score: 25
  • Desktop PageSpeed Score: 32
  • Accessibility score: noticeably lower than best-practice benchmarks
After a focused round of Shopify performance optimization, we achieved:
  • Mobile score: 25 → 95
  • Desktop score: 32 → 97
  • Improved accessibility and overall Core Web Vitals
Below is a detailed breakdown of what we fixed, how we fixed it, and what other Shopify store owners can learn from this project.

The Challenge – Great Brand, Slow Store

Kazari’s store was built on Shopify with a visually rich layout: hero banners, high-resolution product images, multiple sections on the homepage, and several apps for analytics, marketing and UX add-ons.
From a brand perspective, it was doing its job. But when we ran PageSpeed Insights and GTmetrix, we saw:
  • High render-blocking scripts and styles
  • Heavy, unoptimized hero and product images
  • Long main-thread blocking time from JavaScript
  • Noticeable layout shifts during load and interaction
  • Legacy JavaScript polyfills loading for outdated browsers
  • Sequential network requests increasing Largest Contentful Paint (LCP) by over 4 seconds
  • Extra weight from unused third-party app code
  • Sub-optimal browser caching, especially in preview mode
These issues are common in Shopify stores – especially when themes, apps and tracking codes grow over time.

What Seven Nodes Did – A Deep Dive into the Optimization

1. Eliminating Render-Blocking Requests

Issue: Critical CSS and JS in layout/theme.liquid, assets/theme.css, and assets/theme.js were blocking the first paint.
What we did
  • Inlined only critical CSS for the initial viewport.
  • Added defer and async to non-critical scripts.
  • Deferred app and tracking scripts to load after the main content.
  • Reordered resources so the browser could start painting above-the-fold content faster.
Impact:
We improved the first visual load by roughly 350ms on mobile, making the store feel instantly more responsive.

2. Image Optimization & Lazy Loading

Issue: Hero banners and product images were larger than their display size, wasting around 318 KB per page.
What we did
  • Resized and compressed images using Shopify filters and modern formats.
  • Made sure all non-critical images used lazy loading in:
    • sections/hero.liquid
    • sections/banner.liquid
    • sections/product-template.liquid
  • Ensured responsive image sizes for different devices.
Impact:
Pages now feel lighter, scrolling is smoother on mobile, and bandwidth usage is significantly reduced without compromising visual quality.

3. Reducing JavaScript Execution & Main Thread Work

Issue:
The store was spending about 11.7 seconds on the main thread and 4.9 seconds executing JavaScript, mostly due to a large theme bundle and app scripts.
What we did
  • Minified and split theme.js into smaller, purpose-based chunks.
  • Deferred non-essential scripts until DOM ready or user interaction.
  • Pushed analytics and tracking scripts to load after initial render.
  • Removed duplicate or unused JS from legacy experiments and apps.
Impact:
Lower CPU usage on mobile devices, faster interactivity, and a noticeable reduction in “jank” when scrolling and tapping.

4. Fixing Forced Reflows & Layout Shifts (CLS)

Issue:
Certain JavaScript functions were triggering forced reflows, causing layout shifts when elements changed size or position while users were interacting.
What we did
  • Audited assets/theme.js and batched DOM reads and writes.
  • Wrapped animations and transitions inside requestAnimationFrame() so the browser could schedule reflows efficiently.
  • Added will-change to frequently animated elements in CSS to give the browser a heads-up for GPU optimization.
Impact:
Lower Cumulative Layout Shift (CLS), smoother animations, and a more stable experience across product pages and the cart.

5. Removing Legacy JavaScript & Polyfills

Issue:
Older polyfills were still being served, adding ~18 KB of unnecessary JS to every page, even though most visitors used modern browsers.
What we did
  • Removed outdated polyfills and configured scripts to serve ES6+ to compatible browsers.
  • Ensured graceful degradation for any edge cases without bloating the main JS bundle.
Impact:
Smaller JS payload, faster parsing, and quicker execution—especially important for lower-end mobile devices.

6. Optimizing the Network Dependency Chain & LCP

Issue:
Some key assets were loading sequentially, slowing down Largest Contentful Paint by ~4.3 seconds.
What we did
  • Used preload on critical assets: hero images, main CSS, and web fonts.
  • Reduced resource dependency chains by deferring app-specific JS.
  • Prioritized content that actually appears above the fold.
Impact:
Faster rendering of the main hero section, better LCP score, and a visually “instant” page for first-time visitors.

7. Cleaning Up Third-Party App Footprint

Issue:
Past experiments had left app snippets and unused embeds in theme.liquid, which were still loading scripts.
What we did
  • Removed unused snippets and app hooks.
  • Combined or replaced overlapping app functionality where possible.
Impact:
Cleaner codebase, fewer network calls, and reduced script execution time.

8. Smarter Browser Caching & Preview Mode Behaviour

Issue:
Key theme files had short cache lifetimes, especially when viewed via preview mode – slowing down returning visits.
What we did
  • Reviewed cache behaviour for theme.js, theme.css and static assets.
  • Extended cache duration for files that rarely change.
  • Educated the client on how preview mode can affect perceived performance.
Impact:
Returning visitors now benefit from cached assets, leading to faster repeat loads and a more consistent experience.
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The Final Numbers – Before vs After

Metric
Before
After
Mobile PageSpeed Score
25
95
Desktop PageSpeed Score
32
97
Largest Contentful Paint (LCP)
High and inconsistent
Significantly reduced
Main Thread Work
11.7s
Much lower & stable
JavaScript Execution Time
4.9s
Optimized & reduced
Accessibility Score
Below best practice
Improved to strong green zone
For Kazari, this means:
  • Faster browsing on 3G/4G mobile connections
  • Less frustration and drop-off on product pages
  • Better readiness for SEO, paid campaigns, and organic discovery
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FAQ – Common Shopify Speed Questions We Hear

Can we push the scores even higher than 95/97?

On Shopify, performance is always a balance between:
  • High-quality visuals
  • Third-party apps (reviews, tracking, personalization, etc.)
  • Business requirements (marketing tags, pixels, scripts)

Are all pages optimized or just the homepage?

Yes, we apply optimizations across:
  • Homepage
  • Collection pages
  • Product pages
Each template is analyzed for heavy scripts, images, and layout issues so that customers have a consistently fast experience across the full funnel.

How long will these improvements last?

Performance is not a one-time task. These gains will last as long as the store is maintained well. Installing heavy apps, uploading large images, or changing themes can affect scores.
We recommend a monthly or quarterly performance review.

What tools did you use?

We used industry-standard tools like:
  • Google PageSpeed Insights
  • GTmetrix
  • Shopify’s own network and theme analysis
These tools help us track Core Web Vitals and maintain real-world performance, not just lab scores.

Maintenance Tips for Store Owners – Keep Your Shopify Store Fast

We also shared a practical maintenance checklist with the client. Here’s a summarized version you can use for your own store:

Layout & Content

  • Keep the homepage simple and focused – fewer sections, more clarity.
  • Highlight top-selling products instead of showing everything.
  • Avoid multiple overlapping pop-ups, sticky bars and heavy animations.

Images & Media

  • Compress product and banner images before uploading (aim for under 200 KB, WebP where possible).
  • Use consistent image dimensions (around 1000–1500px wide for main product images).
  • Don’t overload product descriptions with large videos or GIFs.

Apps & Scripts

  • Remove unused or expired discount apps/codes.
  • Avoid using more than one analytics/tracking app where possible—consolidate.
  • Turn off unnecessary visual effects in the theme (parallax, complex transitions, auto-playing sliders).

Design Choices

  • Stick to 1–2 font families to reduce font downloads.
  • Use lightweight themes or well-optimized premium themes.

Ongoing Monitoring

  • Run a quick PageSpeed Insights test every few months.
  • Review new apps and features for performance impact before enabling them across the store.

What This Case Study Proves

This project with Kazari.co.in shows that:
  • You don’t have to sacrifice design to achieve fast performance.
  • Thoughtful optimization of scripts, images, and network priorities can move scores from the 20s to the 90s.
  • A structured approach to Shopify speed optimization can improve not just lab metrics, but real-world customer experience.
At Seven Nodes, we specialize in turning under-performing eCommerce sites into fast, resilient, and conversion-ready experiences.

Need Help with Your Shopify Store Speed?

If your Shopify store:
  • Feels slow on mobile
  • Scores poorly on PageSpeed Insights
  • Relies on multiple apps and tracking codes
…it’s a good time to audit and optimize.
Seven Nodes can help you:
  • Audit your theme, apps, and scripts
  • Optimize Core Web Vitals for SEO and ads
  • Improve performance without breaking your design or store logic
Let’s talk about your store

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