Core Web Vitals Comparison Reveals Gap Between Open Source and Proprietary Platforms

Open source CMS platforms trail significantly behind proprietary systems in Core Web Vitals performance, with WordPress falling last at 46.28% compared to top-performer Duda at 84.87%, according to the November 2025 HTTPArchive Technology Report.

The report shows a surprising trend where closed-source proprietary platforms dominate Core Web Vitals metrics that measure website speed, stability, and responsiveness—factors crucial for user experience and business performance.

The Performance Gap Between Platform Types

The November 2025 data compiled by the open source HTTPArchive community reveals a stark contrast in how different content management systems (CMS) handle Core Web Vitals (CWV). The ranking results demonstrate a clear pattern:

Proprietary platforms lead the pack

Duda maintains its long-standing position as the top performer with an impressive 84.87% of sites passing Core Web Vitals standards. This makes it the only platform in the comparison where more than four out of five sites achieve good CWV scores.

Wix follows in second place with 74.86% of sites meeting CWV standards, while Squarespace rounds out the proprietary platform dominance at third place with 70.39%.

"The gap between Duda and WordPress in the November 2025 comparison was nearly 40 percentage points, 38.59 percentage points to be exact," notes Roger Montti, who compiled the report analysis.

Open source platforms struggle

Drupal leads the open source contenders but sits in fourth place overall with 63.27% of sites passing CWV tests. This positions Drupal squarely in the middle of the comparison, well below the three proprietary platforms.

Joomla ranks fifth with 56.92% of sites passing, while WordPress—despite being the most popular CMS globally—ranks last with only 46.28% of sites meeting CWV thresholds.

This creates what Montti describes as a "curious situation" where all three open source platforms occupy the bottom positions in the comparison, with WordPress "decisively last" at nearly 10 percentage points behind fifth-place Joomla.

The significant performance disparity highlights the ongoing challenges in balancing open source flexibility against proprietary optimization advantages that many businesses must consider when selecting a platform.

Why Core Web Vitals Matter

Core Web Vitals measure three specific aspects of user experience:

1. Loading performance (Largest Contentful Paint)
2. Visual stability (Cumulative Layout Shift)
3. Interactivity (First Input Delay)

While the technical details might seem abstract, the real-world implications are significant for website owners. Sites that perform well on these metrics typically see:

• Lower bounce rates
• Higher engagement metrics
• Improved conversion rates
• Better ad performance
• Potentially better SEO performance

"Websites that load quickly and respond smoothly keep visitors engaged and tend to perform better in terms of sales, reads, and ad impressions, while sites that fall short frustrate users, increase bounce rates, and perform less well for business goals," the report explains.

Beyond just rankings, these performance metrics directly impact business results through improved user experience. According to a study by Deloitte Digital, even a 0.1-second improvement in site speed can boost conversion rates by up to 8% for retail sites and 10% for travel sites.

Data Collection Methodology

The Core Web Vitals Technology Report combines two reliable data sources:

1. Chrome UX Report (CrUX): Collects real-world performance data from opted-in Chrome users as they browse the web, providing insights into how actual visitors experience websites.

2. HTTP Archive: Conducts lab-based tests analyzing how sites are built and whether they follow performance best practices.

Together, these datasets provide a comprehensive view of how each CMS performs under real-world conditions across millions of websites.

Addressing WordPress's Poor Performance

The report raises questions about why WordPress—the platform powering approximately 43% of all websites—performs so poorly on Core Web Vitals metrics.

"While an argument can be made that the WordPress ecosystem of plugins and themes may be to blame for the low CWV scores, the fact remains that WordPress is dead last in this comparison," Montti states.

He suggests a potential solution: "Perhaps WordPress needs to become more proactive about how themes and plugins perform, such as come up with standards that they have to meet in order to gain a performance certification. That might cause plugin and theme makers to prioritize performance."

WordPress site owners should consider implementing comprehensive web performance optimization strategies to overcome these platform-specific challenges, especially since performance has such profound effects on user engagement and conversion rates.

SEO Implications

The relationship between Core Web Vitals and search rankings remains a topic of debate. While Google has confirmed CWV as a ranking factor, its impact appears relatively minor compared to content relevance and other traditional SEO factors.

"Some people insist that Core Web Vitals make a significant contribution to their rankings and I believe them. But in general, the fact is that CWV performance is a minor ranking factor," says Montti.

However, he emphasizes that performance still matters significantly for "outcomes that are immediate and measurable, such as user experience and conversions."

Businesses should recognize that effective website design directly influences SEO performance, with Core Web Vitals being just one aspect of a comprehensive optimization strategy.

Using This Information

Website owners can leverage these findings in several ways:

1. Platform selection considerations: When choosing a new CMS, consider the performance implications alongside functionality needs.

2. Performance optimization: WordPress users should prioritize performance optimization through proper hosting, caching, and careful plugin selection.

3. Business case for upgrades: Use this data to build a business case for investing in performance improvements by connecting speed metrics to conversion rates.

The HTTPArchive report provides valuable benchmarking data for digital marketers and developers to understand where their platform stands in the performance landscape and what improvements might be needed.

Performance Monitoring Recommendations

For website owners concerned about Core Web Vitals performance, implementing a regular monitoring routine is essential:

• Set up regular CWV monitoring using tools like Google Search Console and PageSpeed Insights
• Analyze competitor performance across your industry to benchmark effectively
• Document performance changes after updates to identify problematic plugins or code
• Establish performance budgets for new features to prevent gradual degradation

As websites continue to grow more complex, these performance metrics will likely remain crucial differentiators in creating positive user experiences that drive business results.