Shopify started scanning the HTML it generates for storefronts to find the stylesheets and scripts that block rendering, then telling browsers to open connections and start downloading those files before the page itself arrives. Eligible pageviews at p75 hit their first contentful paint 76ms sooner and their largest contentful paint 100ms sooner, by Shopify’s own measurement, and neither merchants nor theme developers had to change anything. The gains are uneven across browsers, since Chromium and Firefox act on preload hints while Safari takes only the connection ones. Shopify’s earlier analysis had found theme-authored hints often made pages slower, especially on mobile, which is why it now sends a short list drawn from each page rather than whatever a theme author wrote in.
