Core Web Vitals are now both a Google ranking input and the closest thing there is to a measure of how a store feels on a mid-range phone, which is how most people now shop. Three metrics carry the weight: Largest Contentful Paint (LCP), how quickly the main content appears; Interaction to Next Paint (INP), how fast the page answers a tap; and Cumulative Layout Shift (CLS), how much the page moves around as it loads. For a fuller treatment of each one and what moves it, see our guide to ecommerce site speed and conversion.
Why most ecommerce stores miss Core Web Vitals
Most stores do not pass. The 2025 Web Almanac, built on real-user Chrome data gathered across millions of sites in July 2025, found that only 48% of mobile sites clear all three thresholds at once. Split by metric, the weak point is obvious: about 62% of mobile pages reach a good LCP, against 77% for INP and 81% for CLS. LCP is the choke point, and it is the one the fastest stores guard most deliberately.
The stores that pass are not doing anything exotic. They are disciplined about one thing: what they refuse to put in front of the first paint. Here are four that get it right, and the single check you can run on your own store.
Four stores that get it right
Allbirds
On its Wool Runner product page, Allbirds ships almost nothing into the first paint except the hero. Thirty-five below-the-fold images are set to load lazily, and assets come off Shopify’s CDN at the Cloudflare edge, with HTTP 103 Early Hints, a server signal that lets the browser begin fetching the critical request before the rest of the HTML arrives. In real-user field data on mobile its LCP is 2.0 seconds, its INP 163 milliseconds, and its CLS effectively zero. Holding three dozen images back until they are needed keeps the network and the main thread clear for the one image that decides LCP.
Taylor Stitch
Taylor Stitch, a mid-size store rather than a giant, gets the fundamental right that many larger sites miss. Its LCP hero sits in the initial HTML instead of being injected later by JavaScript, and it ships with an eighteen-entry responsive image set, so the browser discovers and right-sizes the image immediately and receives it as AVIF from Shopify’s CDN. Its field data on mobile is LCP 1.5 seconds, INP 137 milliseconds, CLS zero. A hero the browser can find and size on first look is the single biggest lever on LCP, and it costs nothing but discipline.
Typology
Typology wins the hardest metric by moving its image weight off the critical path. Its product images run through an image CDN and arrive as AVIF inside picture elements, behind a thirty-entry responsive set, and the hero is explicitly preloaded at high priority. On mobile its LCP is 1.8 seconds and its CLS 0.06, both comfortably good; its INP, at 213 milliseconds, sits just over the 200-millisecond line and is the one metric it has left to close. The page loads only a single external script, which is why interactivity lands so near to passing rather than far short of it. Reformatting and right-sizing images at the CDN is what protects LCP here; a lean third-party footprint is what keeps INP within reach.
Sézane
Sézane posts the cleanest result of the four. It runs every image through a Cloudinary pipeline that tunes quality automatically and renders each one at an explicit, right-sized width rather than shipping a single oversized master, so a phone never pulls down more image than its screen can use. Its field data on mobile is LCP 0.9 seconds, INP 128 milliseconds, CLS zero, a clean pass on all three and the fastest main paint in the set. Right-sizing at the source is the quiet lever here: the image that decides LCP arrives already scaled to the device that asked for it, so there is nothing left to shrink on the way in.
What the fastest stores have in common
Speed is not won by dropping a fast theme or a caching plugin on top of a heavy page. It is won by what the page refuses to ship before the first paint. The four stores above make the same trade in different places: preload the one thing that has to appear first, defer or drop everything that does not, and right-size the media so the browser never decodes more pixels than the screen can show. The technique varies; the principle does not. What separates the stores that pass ecommerce Core Web Vitals from the ones that miss is not budget or a clever trick, but discipline about what loads first. A fast store is a disciplined store, not a clever one.
The single check for your own store: open one of your product pages in PageSpeed Insights, look at the mobile field data, find the element it names as your LCP, and confirm that element is preloaded and not waiting behind a slider, a video, or a third-party script. That one check explains most failing LCP scores on its own.
Run a free scan of your store to find your LCP element, see whether your product pages pass Core Web Vitals, and learn where the time is going.