App Speed Report · Updated March 2026
Does Checkout Plus Slow Down Your Shopify Store?
Speed impact analysis of Checkout Plus (Checkout Customization) — how much it affects your page load time, what scripts it loads, and how to mitigate the performance cost.
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Checkout Plus Speed Impact Summary
1
Scripts Loaded
60KB
Total Script Size
80-150ms
Avg. Load Time Impact
App Name
Checkout Plus
Category
Checkout Customization
Impact Level
Low
How Checkout Plus Affects Your Store Speed
Checkout Plus adds customizations to the checkout page (gift messages, delivery instructions, trust badges). Its impact is primarily on the checkout page itself.
When a visitor lands on your store, Checkout Plus loads 1 JavaScript file totaling approximately 60KB. 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 80-150ms 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 Checkout Plus adds 80-150ms to your page load, that's a measurable impact on your bottom line.
Checkout Plus has a relatively low speed impact compared to other Shopify apps. If you're looking to improve speed, focus on higher-impact apps first before optimizing Checkout Plus.
What These Scripts Do
Checkout Plus's scripts handle its core checkout customization functionality on your storefront. This typically includes:
- • Core functionality script — The main JavaScript bundle that powers Checkout Plus's features on your pages
The problem isn't that these scripts exist — it's that they often load synchronously and on every page, even pages where Checkout Plus's functionality isn't needed. A visitor browsing your blog doesn't need Checkout Plus's full checkout customization scripts loading and executing.
How to Reduce Checkout Plus's Speed Impact
You don't have to choose between Checkout Plus's functionality and a fast store. Here's how to minimize its performance impact while keeping the features you need:
Checkout Plus only affects checkout pages — minimal storefront impact
Verify no scripts are leaking to non-checkout storefront pages
Keep checkout customizations minimal — each added widget increases checkout page load time
Checkout Plus is a low-priority optimization target for general storefront speed
Focus optimization on apps that load scripts across all pages instead
🔍 SEO impact: Reducing Checkout Plus'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 Checkout Plus
Complete these steps to minimize Checkout Plus's speed impact
The Bigger Picture: App Bloat on Shopify
Checkout Plus 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 Checkout Plus adds 80-150ms 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 Checkout Plus), and optimizes how they all load — deferring non-essential scripts, reducing blocking time, and ensuring your critical page content loads first.
⚡ See How Checkout Plus Affects Your Store
Thunder scans your installed apps — including Checkout Plus — 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 Checkout Plus slow down Shopify stores?
Checkout Plus has a low speed impact on Shopify stores, typically adding 80-150ms to page load time. It loads 1 script totaling approximately 60KB. 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 Checkout Plus affect my PageSpeed score?
Checkout Plus typically reduces your PageSpeed Insights mobile score by 3-5 points depending on your store's baseline performance and other installed apps. The 60KB 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 Checkout Plus to improve speed?
Not necessarily. Checkout Plus provides valuable functionality (checkout customization) 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 Checkout Plus and still have a fast Shopify store?
Yes. Many high-performing Shopify stores use Checkout Plus successfully. The key is optimization: don't load Checkout Plus'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 Checkout Plus's JavaScript until after your critical content has loaded. A well-optimized store with Checkout Plus can still score 80+ on PageSpeed mobile.
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