TTFB (Time to First Byte)
Time to First Byte is the time between a user's browser making an HTTP request and receiving the first byte of data from the server. A TTFB under 800ms is considered 'Good' by Google. It's the foundational speed metric — everything else depends on it.
Why It Matters for Shopify Stores
TTFB is the starting gun for all other performance metrics. A slow TTFB (over 1.5 seconds) means every other metric — FCP, LCP — will also be slow, regardless of how optimized your images are. Shopify stores benefit from Shopify's global CDN, but pages with complex Liquid rendering, large apps, or heavy theme code can slow TTFB. Reducing TTFB through caching, CDN use, and server-side optimization creates a performance improvement that benefits every page.
How to Check Your Store
Chrome DevTools Network tab shows TTFB as the 'Waiting' time on any request. WebPageTest.org provides detailed TTFB analysis. Google PageSpeed Insights also shows server response time diagnostics.
Use the free shopify speed test toolHow to Fix It
Shopify handles most server-side performance. Focus on: reducing Liquid complexity in your theme, minimizing the number of API calls during page load, and using browser caching headers. If on Shopify Plus, ensure you're leveraging Shopify's edge caching.
Related Terms
FCP (First Contentful Paint)
Core Web VitalsFirst Contentful Paint marks the point when the browser first renders any text, image, or non-white content to the screen.
LCP (Largest Contentful Paint)
Core Web VitalsLargest Contentful Paint measures how long it takes for the largest visible content element on a page — usually a hero image or headline — to finish loading.
Edge Caching
PerformanceEdge caching stores copies of your store's pages, images, and assets at CDN edge servers around the world — so future requests are served from the closest edge location rather than your origin server.
Shopify CDN
ShopifyShopify's CDN (Content Delivery Network) automatically serves your store's images, JavaScript, and CSS from servers geographically close to your visitors.
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