App Speed Report · Updated March 2026
Does Rebuy Slow Down Your Shopify Store?
Speed impact analysis of Rebuy (Upsell & Cross-sell) — how much it affects your page load time, what scripts it loads, and how to mitigate the performance cost.
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Rebuy Speed Impact Summary
3
Scripts Loaded
190KB
Total Script Size
200-380ms
Avg. Load Time Impact
App Name
Rebuy
Category
Upsell & Cross-sell
Impact Level
Medium
How Rebuy Affects Your Store Speed
Rebuy provides smart product recommendations, upsells, and cross-sells powered by AI. It loads recommendation widgets on product, cart, and checkout pages.
When a visitor lands on your store, Rebuy loads 3 JavaScript files totaling approximately 190KB. These scripts need to be downloaded, parsed, and executed by the browser — all of which takes time and competes with your core page content for network bandwidth and CPU resources.
The measured impact is 200-380ms of additional page load time. To put that in perspective: Google research shows that each additional 100ms of load time reduces conversion rates by up to 7%. If Rebuy adds 200-380ms to your page load, that's a measurable impact on your bottom line.
Rebuy's medium impact means it's contributing noticeably to your load time but isn't the worst offender. Combined with other apps, however, the cumulative effect can be significant.
What These Scripts Do
Rebuy's scripts handle its core upsell & cross-sell functionality on your storefront. This typically includes:
- • Core functionality script — The main JavaScript bundle that powers Rebuy's features on your pages
- • Tracking/analytics script — Monitors user interactions and behavior for Rebuy's dashboard and reporting
- • UI/widget scripts — Renders visual elements like popups, widgets, or embedded components on your storefront
The problem isn't that these scripts exist — it's that they often load synchronously and on every page, even pages where Rebuy's functionality isn't needed. A visitor browsing your blog doesn't need Rebuy's full upsell & cross-sell scripts loading and executing.
How to Reduce Rebuy's Speed Impact
You don't have to choose between Rebuy's functionality and a fast store. Here's how to minimize its performance impact while keeping the features you need:
Limit Rebuy widgets to cart and product pages — disable on homepage and collection pages
Reduce recommendation widget placements to 2 per page maximum
Use Rebuy's lightweight embed mode instead of the full interactive widget
Disable Rebuy on mobile if mobile upsell conversion rates are low
Monitor Rebuy's conversion data — remove widgets that don't generate measurable revenue
Defer Rebuy widget initialization to after main content loads
🔍 SEO impact: Reducing Rebuy's speed impact helps your store pass Core Web Vitals — Google's official ranking signal since 2021. Better speed = higher rankings = more organic traffic.
Quick Optimization Checklist for Rebuy
Complete these steps to minimize Rebuy's speed impact
The Bigger Picture: App Bloat on Shopify
Rebuy is just one app on your store. The average Shopify store has 15-25 apps installed, and each one adds its own JavaScript and CSS to your storefront. The cumulative effect is what really kills your speed score.
Think about it: if Rebuy adds 200-380ms and you have 10+ other apps each adding 100-400ms, your total third-party script overhead could be 2-5 seconds. That's the difference between a store that converts and one that loses visitors before the page even loads.
Manually optimizing each app's loading behavior is time-consuming and requires technical knowledge. You'd need to edit theme files, understand JavaScript loading patterns, and constantly monitor for regressions when apps update their scripts.
This is exactly the problem Thunder was built to solve. Thunder automatically scans every app on your store, measures each one's actual speed impact (including Rebuy), and optimizes how they all load — deferring non-essential scripts, reducing blocking time, and ensuring your critical page content loads first.
⚡ See How Rebuy Affects Your Store
Thunder scans your installed apps — including Rebuy — and shows you exactly how much each one impacts your speed. Then it fixes them automatically.
Install Thunder Free →Free plan available · Scans all your apps · No code changes required
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Frequently Asked Questions
Does Rebuy slow down Shopify stores?
Rebuy has a medium speed impact on Shopify stores, typically adding 200-380ms to page load time. It loads 3 scripts totaling approximately 190KB. While this isn't negligible, you can mitigate the impact by deferring its scripts, limiting which pages it loads on, and using a speed optimization app like Thunder to manage its loading behavior.
How much does Rebuy affect my PageSpeed score?
Rebuy typically reduces your PageSpeed Insights mobile score by 3-10 points depending on your store's baseline performance and other installed apps. The 190KB of JavaScript it loads contributes to longer Time to Interactive (TTI) and potentially affects Largest Contentful Paint (LCP) if scripts block rendering. The actual impact varies — stores with fewer apps will notice it more.
Should I uninstall Rebuy to improve speed?
Not necessarily. Rebuy provides valuable functionality (upsell & cross-sell) that likely benefits your store. Instead of uninstalling, optimize how it loads: defer non-critical scripts, limit it to pages where it's needed, and use Thunder to automatically manage its loading priority. Only uninstall if you're not actively using the app or if the speed cost outweighs the business value.
Can I use Rebuy and still have a fast Shopify store?
Yes. Many high-performing Shopify stores use Rebuy successfully. The key is optimization: don't load Rebuy's scripts on pages where they're not needed, compress your images to offset the script overhead, and use a tool like Thunder to defer Rebuy's JavaScript until after your critical content has loaded. A well-optimized store with Rebuy can still score 80+ on PageSpeed mobile.
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