You have seen a speed score for your website, it was not good, and somewhere along the way someone told you the platform is to blame.
It almost certainly is not. Here is what the evidence actually shows, and what is more likely going on with your site.
Wix and Squarespace are not slow platforms
The Core Web Vitals Technology Report tracks how real visitors experience millions of websites, grouped by the platform each one is built on. In the November 2025 snapshot,
Wix ranked second with 74.9% of sites passing and Squarespace third at 70.4%.
WordPress came last, at 46.3%.
For context,
only 48% of mobile websites across the entire web pass.
So if you are on Wix or Squarespace, you are on a platform performing better than most of the web. Both companies have invested heavily in speed, and because they control the whole stack-the hosting, the delivery and the rendering-their customers inherit that work without lifting a finger.
Which raises the more useful question.
So why is your score bad?
Two possible reasons, and it matters a great deal which one you are looking at.
A platform average is not your site.
Roughly a quarter of Wix sites and a third of Squarespace sites still fail. Someone has to be in that group, and what puts them there is almost always what was added to the site, not the platform underneath it.
You may be reading the wrong number.
This is the one that catches almost everybody.
Most free speed tests hand you a single headline score out of 100. That number is a laboratory simulation. Your page is loaded once, on a virtual mid-range phone, over a deliberately throttled connection. It is built to be pessimistic, and it can vary noticeably between two runs on the same unchanged page.
Separately, and far less visibly, Google collects anonymised performance data from real visitors to your site over a rolling 28-day window. That is the measurement Google itself uses to judge your site, and it is the only one that reflects what your customers genuinely experience on their own phones and connections.
The two regularly disagree, sometimes dramatically. A site can score in the thirties on a lab test and still pass its real-world assessment comfortably.
Before you spend a weekend tearing your homepage apart, it is worth establishing which of those two numbers frightened you.
If the real-world data is genuinely poor
Then something on the page is at fault, and it is usually one of five things. Across the web,
loading speed is the main drag: 62% of mobile sites pass the loading measure, against 77% for responsiveness and 81% for visual stability.
Which points squarely at images and server response.
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Images.
Uploading a photo straight off your phone ships a 4MB file where 200KB would look identical.
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Apps.
Every add-on injects its own scripts and stylesheets.
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Embeds.
Chat widgets, booking tools, social feeds and duplicate tracking scripts all compete with your visitor for the browser's attention.
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Fonts.
Two families, three weights between them. Every additional one is another download that delays your text appearing.
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Motion.
Homepage sliders, parallax effects and video backgrounds are expensive, and most visitors never see past the first slide anyway.
Why any of this matters
Not primarily for your rankings. Speed is a ranking signal, but
a fairly minor one.
It matters because of what speed does to behaviour.
Deloitte and Google, testing across 37 brands, found that a 0.1 second improvement in mobile load speed lifted retail conversion rates by 8.4%.
One tenth of a second, below the threshold of conscious perception, and it moved every stage of the funnel.
Vodafone Italy ran an A/B test on two visually identical pages where one loaded 31% faster, and the faster page produced 8% more sales.
That is the whole argument. Not rankings. Revenue.
When the platform genuinely is the limit
Occasionally it is. If you have stripped the site back to essentials and real visitors are still having a slow experience, you are up against a ceiling you do not control, because you cannot change the code the platform ships on every page. That is a genuine constraint, and it is worth knowing about before you spend another year optimising around it.
But it is the exception, not the place to start.
What a platform built for speed looks like
There is a pattern in that Core Web Vitals table worth sitting with.
The top three performers are all closed, proprietary platforms. The bottom three are all open source.
That is not a coincidence, and it is not about open source being badly made. It is about who controls the stack.
When one organisation owns the hosting, the delivery, the rendering and the editing tools, performance work ships to every site at once and nobody can install something that breaks it. When a site is assembled from a theme plus a dozen third-party plugins, each maintained by a different developer to a different standard, performance becomes something you have to defend rather than something you inherit.
Our sites are built on the SoNET Web Engine, a single-source platform first deployed in 2007 and refined continuously across the nineteen years since. No plugins, no third-party modules, no bolt-on architecture. It sits in the same category as the platforms topping that table, for the same structural reasons.
The difference is what sits on top of it. Wix, Squarespace and Duda are self-service tools: you get the architecture, then you are on your own for the design, the content, the search strategy and the five things listed above that people accidentally do to their own sites. We build, populate and maintain the site for you, which means the things that drag performance down never get added in the first place.
Not sure which situation you are in?
We will look at what your real visitors experience rather than a one-off simulation, and tell you plainly whether the problem is your content, your setup or the platform itself. Free, in plain English, within two working days. If nothing needs fixing, we will tell you that too.
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Diane Hinds is a Director at Site Spark, the web development arm of The Entertainment Bureau, a PR and brand agency for arts and entertainment clients. Site Spark builds websites.
Sources
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Montti, R. (2025), Core Web Vitals Champ: Open Source Versus Proprietary Platforms, Search Engine Journal, 19 December 2025.
searchenginejournal.com
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HTTP Archive (2025), Web Almanac 2025, Performance chapter.
almanac.httparchive.org
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Deloitte Digital and Google (2020), Milliseconds Make Millions.
web.dev
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Google (2021), The business impact of Core Web Vitals.
web.dev
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HTTP Archive (2026), Core Web Vitals Technology Report.
httparchive.org
Platform pass rates are from the November 2025 snapshot and change month to month. Figures correct at the time of writing.