Pass rate before and after a move to a headless front end, by origin platform
| Move | Pass before | Pass after | Change (points) | Median LCP change | Sites |
|---|---|---|---|---|---|
| Shopify to Next.js | 41.5% | 13.3% | -28.2 | +86 ms | 45 |
| Magento to Next.js | 39.5% | 18.5% | -21.0 | -143 ms | 81 |
| WooCommerce to Next.js | 29.0% | 21.5% | -7.5 | -502 ms | 123 |
| All four platforms to Next.js or Nuxt | 31.6% | 18.1% | -13.5 | -209 ms | 306 |
Source: PageSpeed Matters, Oct 2026. The last row also includes Salesforce Commerce Cloud and Nuxt moves, so it differs from the 249-store headline group.
Summary
Headless commerce, a custom JavaScript front end on top of a store platform, is often sold as the fast option. We checked what happened to real-user Core Web Vitals on stores that made the switch.
It went the other way. 249 top 1M stores that moved from WooCommerce, Magento or Shopify to a Next.js front end went from a 34.7% Core Web Vitals pass rate to 19.0%. The drop came from responsiveness and layout stability, not loading, and it happened even though headless pages were lighter.
What we measured
We used HTTP Archive monthly crawls of the top 1M sites from Sept 2024 to Sept 2026 to find platform switches. A switch counts when a site was detected on one platform for 3+ months and then on another for 3+ months, with the destination detected as Next.js or Nuxt. For each store we compared the share of months that passed Core Web Vitals in months 2 to 4 before the switch with months 1 to 3 after it, using Chrome UX Report field data, then averaged across stores.
We report two groups. The headline group is 249 stores that moved from WooCommerce, Magento or Shopify to Next.js. The wider group is 306 stores that moved from WooCommerce, Magento, Salesforce Commerce Cloud or Shopify to Next.js or Nuxt; Salesforce Commerce Cloud and Nuxt-only moves are too small to report on their own.
Headless stores may keep the old platform as the backend, and many moves come with a redesign. So this shows what happened after the switch, not what a framework causes.
Pass rates fell after the move to Next.js
Before the switch, the 249 stores passed Core Web Vitals 34.7% of the time, about a third of months. After it, they passed 19.0% of the time, under one month in five.
The wider group of 306 stores tells the same story: the pass rate fell from 31.6% to 18.1%. 28.8% of those stores got worse and 14.1% improved, so about twice as many lost ground as gained it.
The contrast with moves to Shopify is sharp. The same origin platforms moving to Shopify improved instead: Magento to Shopify went from 26.5% to 59.6% passing (341 stores), and WooCommerce to Shopify from 26.1% to 57.6% (514).
19.0%
Core Web Vitals pass rate of 249 stores in months 1 to 3 after moving from WooCommerce, Magento or Shopify to Next.js, down from 34.7% before.
Shopify and Magento stores fell furthest
The steepest drops came from the platforms that started highest. Shopify to Next.js fell from 41.5% to 13.3% (45 stores), a 28.2 point drop. Magento to Next.js fell from 39.5% to 18.5% (81 stores).
WooCommerce stores lost less, going from 29.0% to 21.5% (123 stores), and their median LCP actually fell 502 ms. For Shopify stores, median LCP rose 86 ms. In every origin group, the pass rate after the move was lower than before.
Responsiveness and layout stability drove the drop
Across the 306 stores, the share of months with good INP fell from 67.3% to 40.3%, and good CLS fell from 70.8% to 52.0%. Good LCP rose from 48.1% to 56.6%. So headless stores tended to load their main content a little sooner, but respond to taps and clicks more slowly and shift more while loading.
The pages were lighter, not heavier: median total weight fell 356 KB and JavaScript 39 KB. Page weight alone does not explain the INP loss. A likely reason is how the JavaScript runs rather than how much of it there is. Client-side rendering and hydration can keep the main thread busy when a shopper first interacts, and content that loads in after the first paint can push the layout around.
Bigger stores fell further
Popular stores did worse than the rest. The 43 headless movers ranked in the top 100K went from 38.0% passing to 8.9%. The 258 ranked lower went from 31.2% to 20.0%.
One possible reason is that bigger stores run more scripts on top of the front end, but this data does not show that directly. The top 100K group is small, so read this as a direction rather than a precise gap.
What this means for your store
A headless rebuild is not a shortcut to passing Core Web Vitals. In this data, every origin group that went headless passed less often afterward. If you are planning one anyway:
- Set INP and CLS targets before you build, not just LCP. Those are the metrics headless stores lost.
- Render product and collection pages on the server, and keep client-side JavaScript for the parts that need it.
- Reserve space for anything that loads late, such as prices, reviews and recommendations, so the layout does not shift.
- Compare against other options. Stores that moved from WooCommerce or Magento to Shopify passed far more often after the move.
- Measure real-user INP and CLS for a few months after launch, and budget time to fix what you find.
Sources
- HTTP Archive monthly crawls of the top 1M sites, Sept 2024 to Sept 2026, with Chrome UX Report field data, analyzed October 2026
- web.dev, Interaction to Next Paint (INP): https://web.dev/articles/inp
Embed this research
Paste this on your site to embed the chart. It links back to the source automatically.
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<script>window.addEventListener("message",function(e){if(e&&e.data&&e.data.psmEmbed==="headless-commerce-speed"&&e.data.height){var f=document.getElementById("psm-headless-commerce-speed");if(f){f.style.height=e.data.height+"px";}}});</script>
<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.pagespeedmatters.com/resources/data-studies/headless-commerce-speed">Headless Commerce Speed 2026: Pass Rate Falls to 19.0% - PageSpeed Matters</a></p>
Frequently asked questions
Is headless commerce faster?
Not in our data. 249 stores that moved from WooCommerce, Magento or Shopify to a Next.js front end went from a 34.7% Core Web Vitals pass rate to 19.0%. Many moves came with a redesign, so this shows what happened, not what the framework causes.
Why do headless stores fail Core Web Vitals?
Mostly on responsiveness and layout stability. Across 306 headless moves, the share of months with good INP fell from 67.3% to 40.3% and good CLS from 70.8% to 52.0%, while good LCP rose from 48.1% to 56.6%.
Does moving from Shopify to Next.js hurt Core Web Vitals?
It did for the 45 stores in our sample, which fell from a 41.5% pass rate to 13.3%. That was the steepest drop of any origin platform.
Are headless pages heavier?
No. Median total page weight fell 356 KB and JavaScript 39 KB after the move, so the drop in INP is not explained by page weight alone.
Responsiveness and layout problems on a new store front end can be found and fixed, and they are far cheaper to design out before launch. Need help with this? See our ecommerce migration services.