Image optimization
Compress, resize, and serve modern formats so product and hero images load fast on mobile.
BigCommerce performance optimization
Faster BigCommerce pages, more completed checkouts
BigCommerce handles hosting reliably, but theme weight, app scripts, and unoptimized product images still slow your store down where it matters most.
Slow category and product pages on BigCommerce mean shoppers leave before they add to cart—and Google ranks faster competitors above you.
For BigCommerce Essentials and Enterprise stores that want measurable speed improvements.
Why BigCommerce stores still struggle with speed
BigCommerce's managed infrastructure removes server configuration headaches, but it does not prevent slow themes, heavy app scripts, or large product images from hurting your scores.
The BigCommerce app marketplace makes it easy to add features—and easy to accumulate scripts that fire on every page load without you realising it.
- Theme JavaScript bundles that have not been reviewed since launch
- Product images uploaded at full resolution without resize or compression
- Multiple marketing and analytics tags loading synchronously
- Widget builder sections adding render-blocking CSS on every template
What we optimize on BigCommerce
Front-end delivery, image pipelines, and app script management—without breaking your theme.
Caching & CDN
Browser and edge caching so repeat visits and global shoppers see snappy pages.
Code cleanup
Remove bloated themes, unused plugins, and render-blocking resources that slow every page.
JavaScript reduction
Defer non-critical scripts and cut third-party tags that delay interactivity.
Core Web Vitals
Target LCP, INP, and CLS with measurable fixes—not vague “performance tweaks.”
Lazy loading
Load below-the-fold media only when needed so the first screen paints quickly.
Font optimization
Subset fonts, preload critical faces, and avoid layout shift from late-loading text.
Server response time
Tune hosting, database queries, and object caching so pages start rendering sooner.
Before & after results
Representative outcomes from optimization projects. Your results depend on stack and traffic.
Home furnishings brand
Before
Mobile score 36
After
Mobile score 74
Image CDN + theme JS audit
Sports equipment store
Before
LCP 4.6s
After
LCP 2.0s
Hero image + font preload
Multi-channel retailer
Before
Checkout INP 420ms
After
Checkout INP 190ms
Script defer + tag audit
How Loadzen helps you get faster
- 1
Audit
We run a deep speed and Core Web Vitals audit on your key templates—home, collection, product, and checkout where relevant.
- 2
Optimization
We implement prioritized fixes: images, scripts, caching, and theme/app bloat—focused on revenue pages first.
- 3
Monitoring
You get ongoing checks so regressions from new apps, themes, or campaigns are caught before they hurt SEO and sales.
Explore other speed services
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Frequently asked questions
Straight answers about timelines, risk, and what to expect.
- Can BigCommerce stores be significantly optimized?
- Yes. While you cannot change server config, theme code, image delivery, and app script management offer significant gains on most stores.
- Will optimization affect my BigCommerce theme?
- We test all changes on a staging channel before touching production. Theme updates are documented and reversible.
- How do you handle BigCommerce app scripts?
- We audit every script loaded by installed apps, identify non-critical ones, and implement async or deferred loading where the app allows it.
- Can you improve BigCommerce checkout speed?
- Yes. Checkout is a high-value template. We profile scripts that fire on that page and reduce main-thread work to improve INP and perceived speed.
- Do you support BigCommerce Enterprise and Stencil themes?
- We work with both standard and Enterprise accounts and all Stencil-based themes, including heavily customized builds.
Related services
Improve PageSpeed Score
PageSpeed optimization service to increase your PageSpeed Insights score on mobile and desktop. Fix low scores with a clear, prioritized plan.
Learn more →Core Web Vitals Fix
Core Web Vitals fix service to improve LCP, INP, and CLS. We diagnose failing metrics and implement fixes that help SEO and user experience.
Learn more →Magento Speed Optimization
Magento 2 speed optimization to reduce load times, fix Core Web Vitals, and improve ecommerce conversion rates. Audit-first, measurable improvements.
Learn more →Get more from your BigCommerce store
Run a free speed test on your store URL. See exactly what is slowing you down.