How to fix slow page on BigCommerce

Steps for BigCommerce

1. Images: In the BigCommerce control panel, go to Products → [product] → Images and upload images at the largest display size needed (BigCommerce serves them via its built-in Akamai CDN and auto-resizes). Keep source images under 1MB; use WebP or high-quality JPEG.
2. Theme JS/CSS: In Storefront → My Themes → Advanced → Edit Theme Files (Stencil CLI locally), add 'defer' to non-critical <script> tags in templates/layout/base.html. Minimize use of custom scripts added via storefront Script Manager (Settings → Script Manager).
3. Script Manager: Go to Settings → Script Manager and audit every third-party script. Remove unused ones; set placement to 'Footer' and load method to 'Defer' for scripts that allow it.
4. CDN: BigCommerce automatically delivers theme assets and images through Akamai CDN — no configuration needed. For additional performance, enable Cloudflare via the BigCommerce App Marketplace (search 'Cloudflare') or configure it at your DNS level.
5. Apps: Review installed apps in Apps → My Apps and uninstall any that are no longer in use, as each may inject additional scripts.

What is slow page?

Page load time is how long it takes for a visitor's browser to fully display your store page. When that time exceeds 3 seconds — a threshold like 9 seconds represents a critical failure — shoppers see a blank or partially loaded screen before they can browse or buy. Search engines measure this speed directly and use it as part of their ranking signals. Slow pages hurt you in two ways at once: fewer people find you, and fewer of those who do actually stay long enough to purchase.

Google officially uses page experience signals, including Core Web Vitals (which are speed-based metrics), as a ranking factor — a slow store can rank lower than a competitor with similar content simply because their pages load faster. Studies consistently show that conversion rates drop roughly 4–5% for every additional second of load time, meaning a page taking 9 seconds could be losing the majority of potential buyers before they ever see your products. Mobile shoppers — who now make up the majority of ecommerce traffic — are hit hardest, since they often have slower connections. Beyond revenue, extremely slow pages can also trigger Google to crawl your site less frequently, limiting how quickly new products and content get indexed.

See the complete Slow page guide for every platform and the full background.