Core Web Vitals: Proprietary CMS Outperforms Open Source

A recent Core Web Vitals Technology Report from the open-source HTTPArchive community has unveiled a stark performance disparity between proprietary and open-source content management systems (CMS). Analyzing November 2025 data, the report highlights that closed-source platforms are significantly outperforming their open-source counterparts in meeting Google's crucial Core Web Vitals (CWV) metrics. This finding raises important questions for web developers and businesses about the impact of CMS choice on user experience and search engine optimization.

Understanding Core Web Vitals

Core Web Vitals (CWV) are a set of metrics developed by Google to quantify the real-world user experience of a website. They measure aspects like loading performance (Largest Contentful Paint - LCP), interactivity (First Input Delay - FID), and visual stability (Cumulative Layout Shift - CLS). Websites that excel in these areas offer a faster, more stable, and responsive experience, leading to higher user engagement, better conversion rates, and improved business outcomes. Conversely, sites with poor CWV scores often frustrate users, increase bounce rates, and underperform against their business objectives. Essentially, CWV scores serve as a critical indicator of a site's overall quality and its performance under actual user conditions.

How Core Web Vitals Performance Data is Collected

The CWV Technology Report synthesizes data from two primary public datasets to provide a comprehensive view of CMS performance:

• Chrome UX Report (CrUX): This dataset gathers anonymized performance metrics from real Chrome users who have opted to share their browsing statistics. CrUX data reflects how actual users experience websites, offering invaluable insights into real-world performance.
• HTTP Archive: Complementing CrUX, the HTTP Archive conducts lab-based tests. These tests systematically analyze website builds and assess their adherence to established performance best practices, providing a technical perspective on site optimization.

By combining these two robust data sources, the report delivers a reliable snapshot of how each content management system performs against Core Web Vitals.

November 2025 Core Web Vitals Rankings: Proprietary Leads

The November 2025 data from the HTTPArchive report reveals a significant performance gap, with proprietary platforms dominating the top spots and open-source systems trailing at the bottom. The highest-ranked CMS achieved an impressive 84.87% pass rate for Core Web Vitals, while the lowest-ranked managed only 46.28%.

Duda: The Top Performer

For November 2025, Duda secured the number one position, with an outstanding 84.87% of sites built on its platform successfully passing Core Web Vitals. Duda was the only CMS in this comparison where more than four out of five websites achieved a good CWV score, continuing its consistent multi-year reign as the top-ranked platform for Core Web Vitals.

Wix Ranks Second

Wix followed in second place, with 74.86% of its sites passing CWV. While trailing Duda by ten percentage points, Wix maintained a comfortable lead of approximately four percentage points over the third-place CMS in the comparison.

Squarespace Secures Third

Squarespace ranked third, achieving a 70.39% CWV pass rate. Its performance positioned it closer to Wix than to Drupal, firmly establishing its place within the top three publishing platforms.

Drupal in the Middle

Drupal ranked fourth, with 63.27% of its sites passing CWV. This score placed Drupal in the middle of the pack, notably below the three leading proprietary site builders. This marks the beginning of a curious trend, as the bottom three CMS platforms in this comparison are all open-source.

Joomla at Fifth

Joomla secured the fifth spot, with 56.92% of its sites passing CWV. Although more than half of Joomla sites met the CWV thresholds, the platform remained significantly behind the top-performing proprietary systems.

WordPress: Last Place

WordPress ranked last among the compared platforms, with only 46.28% of its sites passing Core Web Vitals. This means fewer than half of WordPress sites met the CWV benchmarks in this snapshot. What makes WordPress's poor ranking particularly striking is its substantial lag, approximately ten percentage points, behind even fifth-place Joomla, firmly cementing its position as decisively last in this comparison.

Why These Performance Gaps Matter

The significant differences in Core Web Vitals scores directly translate into tangible variations in user experience. Platforms at the top of the ranking consistently deliver faster and more stable website experiences across a larger proportion of their sites. Conversely, platforms at the bottom expose a greater number of users to slower, less responsive, and visually unstable pages. The performance gap between Duda and WordPress in the November 2025 comparison was nearly 40 percentage points, specifically 38.59 percentage points, underscoring the profound impact of CMS choice.

While arguments often point to WordPress's extensive ecosystem of plugins and themes as a potential culprit for its low CWV scores, the fact remains that WordPress is dead last in this comparison. This situation suggests a need for WordPress to become more proactive in addressing performance. Implementing stricter standards or a performance certification process for themes and plugins could incentivize developers to prioritize optimization, ultimately improving the platform's overall Core Web Vitals performance.

Does Your CMS Choice Impact Search Rankings?

The debate surrounding whether the choice of content management system directly influences search rankings is ongoing. Some proponents argue that WordPress's flexibility and vast plugin ecosystem make it easier to optimize for Google. However, proprietary platforms like Duda, Wix, and Squarespace have made significant strides, focusing on providing robust and competitive SEO functionalities that automate a wide array of technical SEO tasks, leveling the playing field.

While some SEO professionals strongly believe that Core Web Vitals contribute significantly to their rankings, it's generally accepted that CWV performance is a relatively minor ranking factor overall. Nevertheless, performance remains a critical element for immediate and measurable outcomes, such as enhancing user experience and driving conversions. Therefore, the insights from the November 2025 HTTPArchive Technology Report should not be overlooked by anyone serious about website success.

The original HTTPArchive report, which is slated for replacement soon, is available here. It's worth noting that the new report may lack the ability to filter by date, a feature present in the current version.