Sites losing more than half their raw-HTML words after a platform switch
| Switch | Lost half or more | Sites |
|---|---|---|
| From Shopify to a JS framework | 38.6% | 57 |
| From WordPress or WooCommerce to a JS framework | 25.0% | 761 |
| From other platforms to a JS framework | 22.8% | 395 |
| Between JS frameworks | 18.0% | 267 |
| All moves to a JS framework | 23.6% | 1,480 |
| All moves to other platforms | 10.5% | 4,433 |
Source: PageSpeed Matters, Oct 2026. Raw-HTML visible words, 2 months before vs 1 month after the switch.
Summary
When a site is rebuilt on a JavaScript framework, its text can move out of the HTML the server sends and into JavaScript that runs in the browser. Anything that reads the page without running that JavaScript then sees less text. We measured how often that happens.
Nearly one in four. 23.6% of top 1M sites that moved to Next.js, Nuxt or Gatsby (350 of 1,480) lost more than half the words in their raw HTML after the move. That is more than double the 10.5% for sites that switched to any other platform.
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. For each site we counted the visible words in the raw HTML the server sends, 2 months before the switch and 1 month after, and kept only sites with a word count in both months.
This measures text in the HTML the server sends, not what Google sees after rendering the page. Some framework sites render on the server and keep their text in the HTML. So these results do not show ranking or indexing losses; they show how much text is available before any JavaScript runs. Gatsby moves are counted in the framework total but are too few to report on their own.
Nearly one in four lost half their HTML text
Of 1,480 sites that moved to Next.js, Nuxt or Gatsby, 350 (23.6%) lost more than half the visible words in their raw HTML between 2 months before the move and 1 month after.
Sites that switched to any other platform lost half their raw-HTML text far less often: 10.5% of 4,433. Some loss is normal in any rebuild, because new templates and new copy change what is on the page. But moves to a JavaScript framework did it more than twice as often, which fits a front end that fills in more of its text in the browser.
23.6%
Share of 1,480 sites that moved to Next.js, Nuxt or Gatsby and lost more than half the visible words in their raw HTML.
The losses sit in a minority of sites
Most framework movers kept their text. The median mover's raw-HTML word count after the move was 98% of what it was before. The large losses are concentrated in a minority of sites, likely those that render pages in the browser rather than on the server.
For some of those sites the loss was close to total. 7.2% of the JavaScript framework movers (107 of 1,480) went from 50 or more words to under 50 in the HTML the server sends, against 1.2% of the 4,433 sites that moved elsewhere. Under 50 words often means the server sends little more than a shell, with the content added by JavaScript.
Shopify movers lost text most often
The previous platform made a difference. Sites leaving Shopify for a JavaScript framework lost half their HTML text 38.6% of the time (22 of 57), the highest rate in the table, though it is also the smallest group.
Sites leaving WordPress or WooCommerce did so 25.0% of the time (190 of 761), and sites leaving other platforms 22.8% (90 of 395). Moves from one JavaScript framework to another lost half their HTML text 18.0% of the time (48 of 267), the lowest of the framework groups. That likely reflects a starting point that already relied on JavaScript, so there was less server-sent text to lose.
Results by target framework
By destination, 24.2% of 1,274 moves to Next.js and 19.8% of 187 moves to Nuxt lost more than half their raw-HTML words. Both are well above the 10.5% for sites that moved to other platforms.
Next.js accounts for most framework moves, so it drives the overall 23.6%. Both frameworks can render pages on the server, so the result depends on how each site was built, not only on which framework it chose.
What this means for your site
If you are rebuilding on a JavaScript framework, make sure the text that matters is in the HTML the server sends:
- Before launch, compare the raw HTML of your key pages on the old and new site. View the page source, or fetch the page without running JavaScript, and check that headings, body copy and links are there.
- Use server-side rendering or static generation for pages you want found in search, rather than rendering them only in the browser.
- Check how Google renders the new pages with the URL Inspection tool in Search Console.
- After launch, recheck a sample of pages each month, since template changes can move text back into JavaScript.
Raw-HTML text is not the same as what Google indexes, but keeping it intact removes one risk from a migration.
Sources
- HTTP Archive monthly crawls of the top 1M sites, Sept 2024 to Sept 2026, analyzed October 2026
- Google Search Central, Understand JavaScript SEO basics: https://developers.google.com/search/docs/crawling-indexing/javascript/javascript-seo-basics
Embed this research
Paste this on your site to embed the chart. It links back to the source automatically.
<iframe id="psm-javascript-framework-migration-seo" src="https://www.pagespeedmatters.com/embed/data-studies/javascript-framework-migration-seo" width="100%" height="600" style="width:100%;border:1px solid #E2E3E1;border-radius:12px" loading="lazy" title="Moving to a JavaScript Framework: Nearly 1 in 4 Sites Lost Half Their HTML Text - PageSpeed Matters"></iframe>
<script>window.addEventListener("message",function(e){if(e&&e.data&&e.data.psmEmbed==="javascript-framework-migration-seo"&&e.data.height){var f=document.getElementById("psm-javascript-framework-migration-seo");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/javascript-framework-migration-seo">Moving to a JavaScript Framework: Nearly 1 in 4 Sites Lost Half Their HTML Text - PageSpeed Matters</a></p>
Frequently asked questions
Do sites lose content when they move to a JavaScript framework?
In the HTML the server sends, often yes. 23.6% of 1,480 sites that moved to Next.js, Nuxt or Gatsby lost more than half their raw-HTML words, against 10.5% of 4,433 sites that moved to other platforms.
Does moving to Next.js hurt SEO?
Our data does not measure rankings or what Google sees after rendering. It shows that 24.2% of 1,274 moves to Next.js lost more than half the words in their raw HTML, which is worth checking before launch.
How do I check whether my text is in the raw HTML?
View the page source or fetch the page without running JavaScript, and check that your headings and body copy are there. In our data, 7.2% of framework movers dropped from 50 or more words to under 50 in the server-sent HTML.
Checking the server-sent HTML of key pages before launch is a simple way to catch content that a rebuild has moved into JavaScript. Need help with this? See our SEO migration services.