Speed & Performance

Three metrics, one 75th-percentile bar, and a mobile test that punishes JavaScript. Here’s the technical, metric-by-metric playbook to get LCP, INP, and CLS into the green on a real Shopify store in 2026.

Your Shopify store is almost always slow because of what’s installed on top of it, not Shopify itself. The biggest culprit is third-party app scripts, followed by large unoptimized images and a heavy theme.