Shopify speed work fails when teams redesign first and audit apps later. Core Web Vitals respond faster to removing weight than to another theme setting.
Baseline mobile scores, remove unused apps, compress hero media, then touch theme code.
| Metric | What to fix first | Owner |
|---|---|---|
| LCP | Hero media size and priority | Theme / media |
| INP | Script budget and heavy apps | Apps / engineering |
| CLS | Late sticky bars and gallery shifts | Theme / UX |
Measure the real pages
Test homepage, a busy collection and a top PDP on mobile. Lab scores alone are not enough. Field data from Search Console or CrUX shows what shoppers feel.
Cut script budget before redesign
List every app that injects storefront JavaScript. Remove overlap. Defer non-critical chat, reviews and personalisation where possible.
Protect LCP and CLS
Give hero images explicit dimensions. Avoid late-loading sticky bars that shove content. Prefer theme-native lazy loading over stacked app loaders.
Watch INP during peak campaigns
Heavy upsell and popup stacks often hurt interaction delay when traffic spikes. Test with campaign apps enabled, not only on a quiet staging theme.
We include Core Web Vitals checks in Shopify maintenance and redesign scopes so speed work stays tied to revenue pages, not vanity homepage scores.
