Table of contents of the article:
In the dynamic world of the web, where every detail can make a difference in rankings and user experience, Google has made a significant qualitative leap in its evaluation methodology. Since Google introduced PageSpeed Insights— tools that for years have been the go-to tool for developers and SEOs to evaluate their site performance —its evolution has led to the advent of Core Web Vitals . This new suite of metrics not only measures a website's efficiency and speed, but goes beyond that, focusing on the actual user experience. By analyzing crucial aspects such as loading time, interactivity, and visual stability, Core Web Vitals offer a more in-depth and comprehensive overview of how a site is perceived by users, highlighting the importance of optimizations that go beyond simple loading times.
I Core Web Vitals: The transition from Vanity Metrics to Crucial Tools
The days of boasting a high PageSpeed Insights score were over. Google now requires a deeper understanding of a site's actual performance. Core Web Vitals have become the epitome of this evolution, marking a clear distinction between what is purely aesthetic and what is crucial to the user experience.
- I Core Web Vitals LAB: This is a set of tests conducted in the laboratory by Google. These tests, while rigorous and detailed, are actually simulations of a site's performance. They don't necessarily reflect the end-user experience, but they are valuable tools for developers. They work like a compass that indicates which direction to move in during the site design and optimization phases. However, it is crucial to understand that while they are indicative, they do not represent the concrete reality of how a site is perceived by users.
- I Core Web Vitals CRUX (Chromium Real User Experience): Here we enter the heart of the user experience. These metrics are based on real data collected by Chromium-based browsers. These include giants like Google Chrome, but also Microsoft Edge, Opera, Brave and many more. Every time a user opens a web page through these browsers, they send Google a series of detailed information about page loading, its interactivity and visual stability. Google, by analyzing this data, extracts an average of the performances of the last 28 days and establishes whether or not the site responds positively to the parameters of the Core Web Vitals, for both desktop and mobile versions.
While LABS tests offer a "theoretical" view of a site's performance, CRUX data provides a "practical" representation, based on real experiences. The latter have become of vital importance in determining the visibility of a site in the Google SERP. In other words, a site may score excellent on LABS tests, but if it falls short of CRUX metrics, its position in search results could suffer severely.
We talked about this extensively and specifically in this post: Core Web Vitals and CRUX Data.
Simply put, a site with a PageSpeed Insights score of 100 doesn't necessarily pass the Core Web Vitals tests , just as a site with a score of 60 isn't necessarily doomed to fail them. For example, one of our clients with an average mobile score of just 50 on PageSpeed Insights still manages to pass the Core Web Vitals test with flying colors . This site is ranked as the 375th most visited site in Italy, with at least 9,2 million unique visitors per month and over 15 million page views, according to data from Similarweb.com and connected Analytics. This demonstrates that the user experience, as measured by the Core Web Vitals , can be excellent even if the PageSpeed Insights score isn't perfect.
The evolution in the pursuit of optimal web performance
In the recent digital era, where a website's speed and efficiency can make the difference between winning and losing customers, attention to performance optimization has become crucial. The renewed emphasis on Core Web Vitals has boosted the optimization solutions industry, bringing to light a series of tools designed to help websites achieve peak performance. These tools not only help improve loading times, but also optimize the interactivity and visual stability of pages, ensuring a superior user experience.
Kleecks CDN and iSmartFrame: The Seeming Magic in Performance Optimization
Among the many options available to developers and website owners, Kleecks CDN and iSmartFrame emerge as two recognized leaders in providing performance-oriented solutions.
- The philosophy behind CDNs: CDNs, or Content Delivery Networks, represent a network of servers distributed in various geographical points, with the aim of serving content to visitors more quickly and efficiently. The main objective of these networks is to minimize the distance between the visitor and the source of web content, ensuring a reduced loading time and a smooth user experience.
- Kleecks CDN and iSmartFrame at work: Both of these solutions, while each having its own specific characteristics, exploit the potential of CDNs and operate as a reverse proxy. In this function, they act as intermediaries between the end user and the site's original server.
The magic happens when they take charge of the source code of a website and optimize it, performing advanced technical operations such as:- Minification: Compress JS and CSS codes, reducing space and making loading faster.
- Converting images: Exchange heavy image formats for lighter and faster formats like WebP, without compromising quality.
- Cache and latency reduction: Thanks to caching mechanisms, frequently requested content is stored and served more quickly, minimizing user waiting times.
- Much more.
- A gift to developers: The beauty of these solutions lies in their nature of PaaS, or Platform as a Service. Instead of manually handling optimization complexities, developers can rely on these platforms to do all the heavy lifting, allowing them to focus on other project challenges without having to dig into application code and troubleshoot of performance by correcting the code.
In-depth analysis of the discrepancy between LABS and CRUX
In our ongoing effort to understand the dynamics of website performance, we've come across a particular dilemma regarding the use of services like Kleecks, iSmartFrame, and other similar optimization tools. While these services promise optimal performance, the reality may be slightly different.
It's ironic, to put it mildly, that companies that market themselves as enterprise leaders in Core Web Vitals and web performance optimization have their own corporate websites, through which they interact with the world, failing to pass Core Web Vitals tests . This raises significant questions about the actual effectiveness of these services and their ability to deliver on their promises to customers.
For example, during our analysis, we found that some of these services, despite being marketed as cutting-edge solutions for improving performance metrics, fail to adequately optimize websites. The following images show the results of tests conducted on these sites, highlighting how they fail to meet the Core Web Vitals standards , despite being supposed to be paragons of excellence in this field.
This phenomenon can be attributed to various factors. In some cases, the optimizations offered may be too general and not specifically tailored to the needs of the individual site. In others, there may be a mismatch between marketing promises and the actual technical capabilities of the services.
Arriving in both cases to have very serious TTFB problems that exceed the second, where Google recommends a TTFB time of less than 200 ms.
In the course of our investigations, we decided to go beyond simple theory and assumptions by examining in detail some customers who make use of these emerging technologies. The goal was to better understand how these technology stacks handle requests and serve content, particularly in response to Google's specific PageSpeed Insight user agent.
After a series of thorough and meticulous tests, we obtained surprisingly enlightening results. We discovered that, when Google PageSpeed Insight detects the user agent, several JavaScript files actually fail to load. This allows the sites to achieve impressively high LABS scores, almost as if they were wearing an optimization mask. However, when it comes to the Core Web Vitals real-world user experience (CRUX) tests , the results are less flattering: not only do they fail these crucial tests, but they also exhibit significant performance deficiencies.
This discovery reveals a problematic practice in which websites are optimized to achieve artificially high scores in PageSpeed Insight tests, masking their true performance. While this approach may temporarily improve the perception of site performance, it doesn't address the fundamental issues that impact user experience. In fact, Core Web Vitals are designed to evaluate actual user interaction with the site, so if a site falls short in these metrics, it means end users may experience longer load times, less fluid interactions, and poor visual stability.
For example, a particularly worrying figure was the very high Time to First Byte (TTFB) , or latency, a key indicator of server response speed that Google recommends always keeping below 200 milliseconds.
In short, it seems absurd to see TTFB of more than a second in sites of companies that propose to optimize Web Performance, resulting a priori not very credible.
To make our findings more accessible and understandable, we've condensed our findings into an analysis video. We invite all interested parties to view it to gain a detailed overview and in-depth understanding of what we have discovered.
Misalignment between synthetic metrics and real data
We've observed that many websites, after integrating these solutions, show exceptional scores when analyzed using Google PageSpeed Insight's LABS tests. However, these scores don't seem consistent with the results provided by Core Web Vitals (CRUX), which represent the site's performance for real users.
In this regard, we wanted to take as an example some sites that we can see in the video above which suggest both the discrepancy and the methodology used to go and verify the modus operandi of these "miraculous CDNs".
The apparent disconnect between these two metrics raises some concerns:
Synthetic LABS Tests: Reliability and Limits in the Real World
Synthetic tests, such as those offered by LABS, are a type of analysis that simulates user behavior on a website in a controlled environment. While they are extremely useful for identifying performance issues in development or optimization, they have some inherent limitations that could make their results less representative of actual user experiences.
How do synthetic tests work?
Such tests are performed in the laboratory, or in virtual environments, where variables such as bandwidth, latency and device resources are standardized or simulated. This allows developers to obtain performance metrics under "ideal" conditions, eliminating the fluctuations that might occur under real-world sailing conditions.
Limitations of Synthetic Tests
- Standardized environments: Because these tests are performed under controlled conditions, they may not account for different combinations of hardware, software, and connectivity that end users may have. A site might work well on a high-end device with a fast connection, but perform poorly on an older device or with a slow connection.
- External interference: Real users might have many tabs open, applications running in the background, or even security software that could affect the performance of a website. These factors are not typically simulated in synthetic tests.
- Caching and User Interactions: While synthetic tests may simulate some of them, they may not fully capture real user behavior, such as scrolling a page, clicking on various items, or how browsers handle caching of a site during subsequent visits.
- Deceptive Strategies: As mentioned earlier, techniques such as cloaking could allow a site to "cheat" synthetic tests by presenting an optimized version when it detects a test in progress. This could result in artificially high performance metrics.
Cloaking: A Deceptive Strategy For Manipulating Google Tests?
The term "cloaking" refers to a search engine optimization (SEO) practice that has raised a lot of controversy over the years. This tactic is based on presenting different versions of a web page to search engines and real users. The main goal behind this maneuver is to manipulate and improve a site's ranking in the search engine results pages (SERPs), by showing engines content that could be seen as more relevant or optimized.
How does cloaking work?
Cloaking is a sophisticated technique used to present different content depending on the user making the request to the server. The fundamental principle on which cloaking is based is the recognition of the User Agent or IP address of the requester.
User Agent recognition
The User Agent is a text string that the browser sends every time it requests a web page, providing information about the browser itself, the operating system and other details. Search engine crawlers, such as Googlebot, use specific User Agents that can be easily identified. When the server receives a request from a User Agent that is recognized as belonging to a crawler, it can respond with content that is optimized for crawling and indexing. For example, it can return a simplified HTML version of the page, which excludes dynamic elements such as JavaScript and complex CSS, making it easier for the crawler to parse the content.
IP address recognition
In addition to the User Agent, the server can also identify crawlers by IP address. Major search engines use known IP ranges, and the server can be configured to recognize these requests and respond accordingly. This method adds an additional layer of control, as User Agents can be spoofed, while IP addresses are more difficult to mask.
Operation example
Let's imagine a web page that intensively uses JavaScript to generate dynamic content. A normal visitor accessing this page will see all the interactive and dynamic elements generated by JavaScript. However, when a search engine crawler like Googlebot visits the same page, the server recognizes the crawler via User Agent or IP address and serves a static HTML version of the page. This static version is more easily indexed by search engines, thus improving the site's SEO.
CDN and Cloaking : A New Paradigm for Data Optimization Core Web Vitals ?
Given the growing emphasis on metrics like Core Web Vitals , one might assume that some CDNs, in their quest to optimize performance, are resorting to cloaking-like tactics. This would mean that when these CDNs detect a LABS test from Google PageSpeed Insight, they might serve a "lightened" or "optimized" version of the site, removing or modifying certain elements to achieve higher scores.
During our investigation, we simulated being a Google bot by modifying our browser's User Agent and noticed that, under certain circumstances, external JavaScript scripts, notoriously heavy and potentially slow, were not loading. This omission, while it may result in seemingly faster loading times during testing, may not reflect the actual user experience.
A dangerous precedent in the WP Optimize plugin for WordPress accused of altering PageSpeed
WP-Optimize, a popular WordPress performance plugin, has been accused of manipulating benchmarks . Gijo Varghese, a web performance developer and creator of the FlyngPress plugin, pointed out that WP-Optimize disables JavaScript during benchmarking tests. His claim was supported by a screenshot showing how the plugin prevents JavaScript files from loading during benchmarking.
This behavior generated negative reactions from the WordPress community. Some compared this tactic to similar scams, such as the Volkswagen emissions scandal. Users expressed disappointment and concern over these deceptive practices. The discussion emphasized the importance of focusing on real user experiences rather than test scores. However, these revelations have damaged trust in WP-Optimize.
Implications and Ethics
The potential discovery of CDN cloaking techniques isn't just a technical detail; it raises deeply rooted ethical and technical questions. When an organization opts for cloaking, it could effectively "mask" a site's true performance, giving the illusion of optimization that isn't actually there. While the primary intent may appear to be to improve performance, what actually happens is a distortion of test results, resulting in a misrepresentation of the site's true capabilities. This can lead developers and website owners to make decisions based on flawed data, leading them off course.
Furthermore, it's crucial to consider the significant financial burden these solutions entail. Fees for some of these CDNs can reach considerable amounts, even several thousand euros per month, which translates into significant monthly expenses over the long term. If these huge sums are spent without achieving a tangible improvement, such as exceeding Core Web Vitals , one might legitimately question whether those resources would have been better spent elsewhere.
Indeed, given the current landscape of web technologies and the growing emphasis on performance, it would make perfect sense to reinvest these funds in more sustainable and permanent solutions. Dedicating resources to hiring or consulting experts, such as dedicated web developers and Linux system administrators specializing in web performance, could offer a much more significant return on investment. These professionals can address and resolve performance issues at the root, offering tailored solutions that not only address immediate challenges but also prevent future problems. And all this with a one-time investment, rather than expensive recurring fees.
The Impact of Javascript on Web Performance: A Double-Edged Sword
Javascript has become one of the fundamental tools in web development, allowing you to create rich, interactive and dynamic web applications. However, like any powerful tool, if not used wisely, it can have unintended consequences on a site's performance.
The Weight of Javascript on the Browser
When a browser loads a web page, it has to parse and execute the Javascript scripts included in the page. This process can be quite onerous, especially when it comes to:
- Large Scripts: Large scripts take longer to download, parse and execute. This can delay the processing of other crucial page elements.
- Intensive Execution: Some scripts, due to their nature or complexity, may be resource-intensive when running, causing a high load on the device's CPU or memory.
- External Dependencies: Scripts that rely on external libraries or call resources from third-party servers can introduce additional latencies, especially if those external resources are slow or unoptimized.
Direct Impacts on the User Experience
Inefficient Javascript execution can lead to various problems, including:
- Rendering block: Scripts that run before the page is fully loaded can block the display of content, leaving users waiting.
- Compromised interactivity: If a script takes too long to respond, user interactions, such as scrolling or clicking, may be delayed or interrupted.
Deceptive Tactics and Test LABS
To score high on synthetic tests like LABS, some CDNs may employ deceptive strategies, such as “skipping” loading problematic Javascript resources. If a website "hides" these scripts during a LABS test, the result will be a page that appears to load much faster, giving the site an artificially high performance score. However, this does not reflect the real experience of the user, who could be exposed to all the problems caused by such scripts in a real browsing context.
Conclusion: The Fine Line Between Metrics and Reality
In the complicated landscape of the web, it's easy to be seduced by perfect numbers and maximum scores. But, as often happens, all that glitters is not always gold. Google PageSpeed Insight, while a vital tool, can sometimes offer partial insight into a website's actual performance.
The Deceptive Charm of Perfect Scores
A LABS score of 100 in Google PageSpeed Insight may seem like the unequivocal testimony of an optimized and performing website. However, it is vital to understand that such a metric, when taken by itself, can be misleading. Some companies, well aware of this, may resort to deceptive tactics to "fix" the LABS tests, in order to exhibit these high scores especially to end customers who do not have the ability or expertise to distinguish the difference between a simulation and the real user experience.
It's important to remember that the Google PageSpeed Insight LABS score is based on simulations and does not necessarily reflect real-world site usage conditions. Simulations can be affected by numerous controllable factors, such as server configuration, content delivery network (CDN), image compression, and the use of advanced caching techniques. These optimizations, while useful, do not always accurately represent the experience of a real user, who may experience significant variations in connection speed, device power, and other environmental factors.
Additionally, some companies may exploit customers' desire for high scores by offering “optimizations” that improve the LABS score without providing any real benefit to the user experience. Such practices may include optimizing exclusively for tests, reducing image quality, or removing crucial features to achieve a better score. This approach is not only deceptive, but can also damage the integrity and usability of the website.
The Flip Side: The Deceived End Customer and the Unimproved Business.
The temptation to impress end customers with perfect scores is understandable. However, often, website owners or stakeholders are completely unaware of the technical nature and nuances of web metrics. Presenting a high LABS score without consistently exceeding Core Web Vitals over the last 28 days might satisfy the customer in the short term, but it won't bring long-term benefits , especially when visitors begin to experience real navigation issues on the site.
When visitors begin to experience real navigation issues, such as slow loading times, delayed interactions, or unstable layouts, the initial positive impression generated by a high LABS score quickly fades . This can lead to decreased user satisfaction, higher abandonment rates, and ultimately, a decline in conversions and revenue.
Additionally, Google uses Core Web Vitals as part of its ranking algorithm, meaning a site's actual performance can directly impact its visibility in search results. A site that consistently outperforms these metrics will be more likely to rank well and attract quality organic traffic. Therefore, focusing solely on LABS scores without considering actual field data can lead to a shortsighted and ineffective optimization strategy.
The Heart of the Matter: Real User Experience
Besides the numbers, what really matters is the CRUX – the real user experience. If a site doesn't deliver consistent and reliable performance to its visitors, perfect LABS scores become irrelevant. And over time, the site's reputation may suffer irreparable damage.
In Final Analysis and Conclusion
While analytics tools like Google PageSpeed Insight are valuable, they should never replace a thorough and authentic user experience assessment. It's imperative for anyone managing a website to look beyond the glowing numbers and focus on what really matters: providing a quality browsing experience for all visitors. Page loading speed is just one aspect of user experience, and a good assessment must also consider usability, accessibility, design consistency, and ease of navigation.
Always remember to be wary of solutions that seem too good to be true; often, they aren't. Promises of drastic and immediate performance improvements without adequate optimization work often prove disappointing. Optimization techniques should be realistic and sustainable, integrating well with the site's structure and content without compromising its integrity or user experience.
Regardless of the performance optimization solution you choose for your website, it's crucial not to stop at the initial results, but rather to analyze and monitor the performance of Core Web Vitals over the medium term. This includes crucial metrics such as LCP (Largest Contentful Paint), FID (First Input Delay), and CLS (Cumulative Layout Shift), which provide a detailed view of how users perceive the speed, interactivity, and visual stability of pages.
Web technology is constantly evolving and what seems to work perfectly today may not be as effective tomorrow. For example, new browser updates, changes in user behavior or new Google guidelines can affect site performance. Therefore, a continuous and prolonged evaluation over time will allow you to have a clear and realistic vision of your site's performance. This practice not only helps to maintain high performance, but also to promptly identify any problems and quickly adapt to technological changes.
Striving to surpass Core Web Vitals shouldn't be a short-term goal, but an ongoing commitment, ensuring a quality browsing experience for your users and a solid reputation for your site in the digital landscape . Investing in continuous improvement of your website's performance helps lay a solid foundation for long-term success, building user loyalty and improving your search engine rankings.
