Page Speed Optimization Checklist

I want an optimization checklist to speed up my Shopify store’s page loads. Note: Sidekick cannot run PageSpeed Insights/Lighthouse or measure live Core Web Vitals — that requires Google’s own tool. This is a generic diagnostic checklist to apply once I have real scores from PageSpeed Insights.

Shopify theme: [THEME_NAME, e.g., Dawn, Impulse, Prestige, custom theme]
Number of installed apps: [APP_COUNT, e.g., 15]
Known speed concerns: [SPEED_CONCERNS, e.g., slow mobile load, large images, too many apps]

Please provide a checklist covering:


  App-bloat review questions to ask about each installed app: does it inject storefront JavaScript, can it be lazy-loaded/deferred, is there a lighter alternative — so I can rank my own [APP_COUNT] apps by likely performance impact.
  Image optimization guidance: target dimensions for hero banners, product images, and thumbnails; when to use WebP/AVIF; when lazy loading below-the-fold images helps.
  Code/theme guidance: what render-blocking CSS/JS typically looks like, when critical-CSS inlining is worth it, and general DOM-size red flags for [THEME_NAME]-based themes.
  A prioritization template (action, estimated effort, expected impact, how to verify after implementing) I can fill in once I run PageSpeed Insights and get real numbers.


Keep this to a generic, theme-agnostic checklist — do not claim to have measured actual Core Web Vitals, PageSpeed scores, or my specific installed apps’ real load-time impact, since Sidekick has no access to that data.