Platforms like Wix exist because most businesses need something live quickly without hiring a developer. Custom code exists because some businesses outgrow templates — on performance, SEO control, accessibility, or brand differentiation. The honest answer is context-dependent.
This article compares what published research actually shows. We did not run our own large-sample Lighthouse study; instead we draw on the HTTP Archive Web Almanac (millions of live CMS sites) and a smaller, independently published PageSpeed comparison. Numbers here are medians and pass rates across real sites — not guarantees for your business.
What the largest dataset shows
Each year, HTTP Archive crawls millions of websites and publishes CMS-level results for Core Web Vitals (real-user field data from Chrome) and Lighthouse scores (lab tests on a throttled mobile connection). That gives a platform-level view of what typical sites deliver — not best-case showcase builds.
In 2025, roughly 48% of all mobile websites passed all three Core Web Vitals thresholds (LCP under 2.5s, INP under 200ms, CLS under 0.1), according to the Web Almanac performance chapter. CMS platforms vary widely around that baseline:
- Wix: 74% of mobile sites passed Core Web Vitals in 2025 (up from 55% in 2024). Median Lighthouse performance score: 64 on mobile, 87 on desktop.
- Squarespace: Among major CMS platforms, Squarespace sits at the lower end for median mobile Lighthouse performance (roughly 30–32 in 2025). Its Core Web Vitals pass rate improved year over year but remains below Wix and Duda.
- WordPress: 45% of mobile sites passed Core Web Vitals in 2025. Median Lighthouse performance: 41 on mobile — reflecting how much implementation choices (themes, plugins, page builders) affect outcomes on an extensible platform.
Source: Web Almanac CMS chapter, 2025.
Two takeaways from those medians. First, managed platforms like Wix have invested heavily in platform-level speed — a typical Wix site is not automatically slow. Second, “custom” is not one category in this data: WordPress with dozens of plugins behaves differently from a lean static build, even though both sit outside a drag-and-drop subscription.
SEO and accessibility scores tell a different story
Lighthouse also audits technical SEO and accessibility. On SEO, the picture flattens: in 2025, Wix and Webflow posted median Lighthouse SEO scores of 100 on mobile and desktop; WordPress, Squarespace, and most other major CMS platforms clustered around 92.
That does not mean every Wix site outranks every custom site. Lighthouse SEO measures baseline technical signals (meta tags, crawlability, structured markup opportunities) — not content quality, backlinks, or local relevance. As the Web Almanac notes, high median SEO scores suggest platforms ship solid technical foundations by default; ranking still depends on strategy and execution.
On accessibility, 2025 medians ranged from 76 (1C-Bitrix) to 95 (Wix) and 94 (Squarespace). Again, these are lab audits on typical implementations. A passing platform median does not certify that your color contrast, heading order, or form labels are correct — those depend on how the site is configured and edited.
What a smaller Lighthouse comparison found
Platform medians describe the middle of the distribution. To see the gap at the page level, web agency TiltStack published a February 2025 PageSpeed comparison of live small-business sites — a deliberately small sample, not a industry-wide study:
- 2 Wix sites (local service businesses)
- 2 Squarespace portfolio sites
- 2 Framer AI-generated sites
- 3 hand-coded Eleventy static sites built by TiltStack
On mobile PageSpeed, they reported average performance scores of 42–61 for Wix, 55–68 for Squarespace, and 91–97 for their Eleventy builds, with correspondingly lower Largest Contentful Paint and Total Blocking Time on the builder sites. They attribute the gap primarily to platform JavaScript payload, CSS delivery, and image handling — not to drag-and-drop editing itself.
Treat this as illustrative, not definitive: nine sites, one agency’s stack, one test methodology. It does show that when a site is engineered with minimal JavaScript and page-specific assets, Lighthouse lab scores can land much higher than typical builder output — which aligns with why lean custom builds remain a performance strategy.
Lab scores are not the same as rankings
Google uses Core Web Vitals field data (what real visitors experience over time), not Lighthouse lab scores, as a ranking signal. As Google’s documentation explains, lab and field data often diverge — you can score well in Lighthouse on a fast laptop and still fail in Chrome UX Report if many users are on slower devices or networks.
Performance still matters for business outcomes. Slow LCP correlates with higher bounce rates; the Web Almanac CMS chapter notes that pages loading beyond three seconds tend to see sharply higher abandonment. Core Web Vitals are a tiebreaker among comparable content, not a substitute for relevance — but if organic search drives revenue, loading speed and interactivity are not cosmetic.
Where builders shine
Speed to launch, predictable monthly pricing, built-in hosting, and approachable editing for non-technical owners. For a proof-of-concept or a very small local service, that can be enough — especially if you keep pages simple and avoid piling on apps.
HTTP Archive data supports a nuanced version of the old “builders are always slow” claim. Wix’s median mobile performance and Core Web Vitals pass rate improved substantially from 2024 to 2025. For a simple site where search is not central, a builder can be a rational starting point.
Where custom code pulls ahead
Lean markup and assets can mean faster loads and fewer surprises in Lighthouse — when the build is actually lean. You own the HTML, CSS, and JavaScript, so you are not locked into a vendor’s component library when you need a precise layout, custom schema markup, or a specific analytics setup. Accessibility fixes can be surgical instead of fighting theme constraints.
Custom does not automatically outperform a well-maintained builder site. It removes platform overhead and lock-in, which matters most when SEO, performance, compliance, or brand differentiation are tied to revenue — or when you expect the site to evolve for years without a full migration.
How to choose
If you are validating an idea, a builder may suffice. If organic search, performance, or compliance is central to revenue — or you need a site to stay fast and flexible for years — custom work often costs less than migrating later.
For a broader look at template economics, ownership, and portability, read our guide: Custom vs. Template: What To Know Before You Pick.
We are biased toward code, but we will tell you if a hybrid path makes more sense. Discuss your constraints openly on our contact page; we will not sell you a rebuild you do not need.