It's a well-established fact that web performance is among the primary factors impacting your SEO performance, not to mention user experience, which will translate to conversions.
Backlinko studied more than 200 of Google's ranking factors. They found that, out of everything, technical SEO (which includes mobile-friendliness, crawlability, website speed, and overall performance), was the third most important factor — behind only content quality and backlinks.
Site speed also significantly impacts your conversion rate. On average, conversions drop 4.42% with every extra second your site takes to load.
Google's free PageSpeed Insights tool is quite helpful for measuring performance and identifying potential issues. But it only provides a limited view. It doesn't cover all aspects of web performance optimization. And relying solely on its feedback will push you down a rabbit hole of misconceptions.
In this guide, we'll take a deep dive into the various factors that impact web performance and how you can take a holistic approach to measuring them.
Google PageSpeed Insights (PSI) is a tool you can use to measure a website's performance. It assigns a score from 0-100 based on how well the site performs in certain metrics. The higher the score, the better.
Simply paste the homepage URL into the PSI search bar, and it'll return a report with actionable advice on improving the site's performance.
Here’s a breakdown of what it excels at:
PSI is great at providing detailed feedback on Core Web Vitals (Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift), which are key metrics that influence user experience. It offers both lab and field data for these metrics, giving you a clear snapshot of how the site performs in real-world conditions.
The tool is particularly helpful in giving you specific suggestions on what to improve. It highlights issues like render-blocking resources, unoptimized images, and opportunities to reduce JavaScript execution time, helping developers and non-developers alike prioritize tasks for optimization.
Mobile page speed is just as important as (if not more than) desktop speed, given that mobile devices account for almost two-thirds of all website traffic and Google prioritizes the mobile version of the site when ranking.
PSI provides separate scores and recommendations for both to help you differentiate.
Its scoring system is easy to understand, with scores broken down into categories: 0-49 (poor), 50-89 (needs improvement), and 90-100 (good). Simplicity is what allows webmasters or web professionals like yourselves to grasp performance at a glance and focus on the areas most needing attention.
Since PSI is powered by Google’s Lighthouse tool, it provides a robust set of data on aspects like accessibility, SEO, and performance. Lighthouse audits are industry-standard for gauging the overall health of a site.
PSI’s accessibility and zero cost make it one of the most commonly used tools for web performance analysis, particularly for smaller businesses and web devs. Anyone can use it without needing specialized technical skills.
PSI is a fantastic starting point for gauging a site's performance and making improvements. However, it has its limitations and should not be the only tool you rely on when optimizing web performance.
Here are some areas where PSI may not be as effective:
PSI relies heavily on lab data, which simulates website performance under controlled conditions. But these simulations don't always represent real-world user experiences, particularly for websites with diverse audiences. Field data (collected from real users) is provided but only if there’s enough traffic, making lab data potentially misleading for low-traffic sites.
While PSI focuses on Core Web Vitals and other key performance metrics, it overlooks several important factors of web performance optimization.
For instance, it doesn't provide insights into backend performance issues like server speed, database optimization, or CDN effectiveness, which can also impact user experience.
The tool treats all issues with equal priority, which can lead to recommendations that may not align with your business goals. For instance, it might suggest eliminating large images or third-party scripts that are central to your client’s branding or site functionality without considering their business value.
PSI’s recommendations can sometimes push you to make changes that have diminishing returns. Over-focusing on getting a perfect score means prioritizing minor issues while ignoring more impactful aspects of search rankings like UX design or content quality.
PSI provides general recommendations that aren't tailored to the specific context of your client’s website or its audience. For instance, reducing image sizes is always encouraged, but the tool doesn’t assess whether this change will significantly impact the user experience based on the devices the audience is using.
The scoring system (0-100) can sometimes oversimplify complex performance issues. A site with a score of 90 might still suffer from real-world performance problems, while a site scoring lower might perform well under certain conditions. This can lead to a false sense of accomplishment or unnecessary concern.
Although PSI integrates Lighthouse’s SEO audits, it mainly focuses on technical aspects like mobile-friendliness and URL structure. It doesn’t consider broader SEO factors such as content relevance, user engagement, or competitive positioning, which are equally important for search rankings.
PageSpeed Insights prioritizes technical performance metrics but doesn’t evaluate important elements like navigation flow, content readability, or overall user satisfaction, which are essential for a holistic user experience.
Expanding beyond PageSpeed Insights metrics will give you a more comprehensive view of website performance, including engagement and user journey analysis.
Core Web Vitals is a set of metrics introduced by Google that focus on key aspects of user experience, particularly around loading, interactivity, and visual stability. Although PageSpeed Insights reports on these, you need to understand their broader importance.
Beyond technical performance, you absolutely have to assess how users interact with your client’s site. This will directly affect conversion rates and the long-term success of the site.
To fully optimize a website, you're going to have to look at all the touchpoints that go into a purchase or conversion, and how buyers interact with the site at different stages of the decision-making process. This is especially important when building a B2B website, where the conversion funnel is sometimes months long, with hundreds of web-based touchpoints.
A funnel analysis allows you to pinpoint precisely where users drop off and uncover opportunities for optimization.
Good news is, fully analyzing and improving your web performance won't cost you an arm and a leg. You have tons of different free tools at your disposal.
Chrome DevTools is a built-in toolset that offers you a wide range of features for real-time analysis, making it an ideal complement to PageSpeed Insights.
There are two essential tabs within DevTools that can help you fine-tune the site: the Performance and Network tabs.
DevTools Performance tab
The Performance tab helps you analyze the runtime performance of a website or web application. It provides a detailed timeline of how various processes, such as rendering, scripting, and network activity, impact a web page's performance.
You can use it to:
The tool captures screenshots of the website during loading to create a filmstrip of images alongside the timeline. This helps you track the user experience and correlate it with performance metrics.
A long delay between the first and last screenshots indicates users are waiting too long to interact with the page.
DevTools Network tab
The Network tab gives detailed insights into how resources (such as HTML, CSS, JavaScript, and images) are loaded. By understanding and optimizing these resources, you can significantly improve the speed, efficiency, and overall performance of the website.
One of the most useful features of the Network tab is the waterfall timeline, which shows how each resource is loaded and the sequence in which they are requested and received. Each resource is represented as a line on the timeline, allowing you to see:
You can also:
And it shows you Time to First Byte (TTFB), which indicates how long it takes for the server to respond to a request. If the TTFB is high, then you know you need to optimize server-side processes (e.g., upgrading hosting, improving database queries).
Lighthouse, an open-source tool from Google, helps enhance web page quality by auditing performance, accessibility, SEO, and best practices. While integrated into tools like PageSpeed Insights and Chrome DevTools, the Lighthouse Command Line Interface (CLI) offers greater flexibility, automation, and deeper insights.
With Lighthouse CLI, you get:
The CLI also allows you to run audits locally, on different servers, or within staging environments. This is particularly useful if you want to test changes before pushing them to production.
WebPageTest is a robust tool for performance testing that provides deeper context to your PageSpeed scores by offering insights into real-world performance across various network conditions (not just lab-simulated ones) and highlighting specific bottlenecks that PageSpeed scores might miss, like unoptimized server-side operations or poor resource prioritization.
One of the key features of WebPageTest is its waterfall chart, which provides a detailed breakdown of each resource’s loading process.
It shows:
It also allows you to simulate website performance across different geographic locations and devices. This enables you to compare performance on mobile and desktop devices and assess how effective your CDN is by checking how your website loads from different regions.
GTmetrix provides its own GTmetrix Grade, which includes Performance and Structure scores. These scores align with PageSpeed metrics but often differ because:
The YSlow grading system, which focuses on optimizing the front-end structure of the website based on rules from Yahoo’s performance team, assesses factors like:
And the video analysis feature records the loading process of the webpage, allowing you to visually analyze how users experience the page load. It'll give you frame-by-frame breakdowns of the site loading and a visual comparison of load times between different.
Russ Jeffrey, Director of Platform Strategy here at Duda, said it best:
"There is no single best tool, but different tools provide different data sets. The Chrome User Experience Report (Crux) offers real-world user performance data, which is ideal."
The Chrome User Experience Report (CrUX) is a public dataset of real user data, aggregated from millions of Chrome users worldwide. It gives you a true reflection of how different users interact with the website under varying network and hardware conditions.
CrUX data can either validate or challenge the results from lab-based tools like PageSpeed Insights.
Google’s BigQuery provides access to the entire CrUX dataset, enabling in-depth analysis of the site's real-world performance.
You can query specific metrics, like:
By querying CrUX data in BigQuery, you can analyze how different user segments experience the site and pinpoint which areas need improvement.
Pingdom is a powerful tool for real-time performance monitoring. It monitors uptime, server response times, and transaction flows on a continuous basis. And it sends you instant alerts whenever a problem comes up.
It does this using a global network of servers to test the website’s speed and performance from over 100 locations worldwide. And it gives you granular insights into every aspect of the website’s loading process — TTFB, render start times, resource load times, you name it.
Pingdom’s scoring system provides similar performance grades to PageSpeed Insights but offers deeper insights into backend performance. While PageSpeed focuses heavily on front-end elements and Core Web Vitals, Pingdom digs into factors like server response times, third-party scripts, and DNS resolution for a more holistic view of your site's performance.
In addition to being the source of all website traffic and conversion/abandonment data, Google Analytics also provides valuable insights into real user behavior and performance over time.
You can use it to:
You can also drill down into performance by device (e.g., mobile vs. desktop), location, and traffic source.
It's also helpful to have a tool that can help you identify exactly when performance issues occur. Both New Relic and Datadog are fantastic tools for server-side monitoring that provide detailed analysis of your page's back-end performance.
These platforms allow you to:
Like I've already hammered home, a well-rounded performance strategy requires you to leverage multiple tools in tandem with PageSpeed Insights. It's the only way you'll optimize both the frontend and backend of your client’s website.
I've already shown you how to use the tools above. Beyond that, here's how to combine insights from these tools for tangible performance improvements:
Three examples of how you can do this are by:
You can also integrate performance data into a holistic dashboard that provides an overview of all these metrics in one place. And you can compare how these metrics correlate with other business KPIs like conversions, revenue, and bounce rates in Google Analytics.
As mentioned earlier, PageSpeed Insights gives weighted scores for frontend optimizations like compressing text-based resources (HTML, CSS, JavaScript), combining and minifying files, and deferring rendering-blocking resources.
You can also reduce the site's Cumulative Layout Shift (CLS) by setting explicit dimensions for images and videos, which you can identify with PSI and validate using Chrome DevTools.
You can leverage A/B testing and personalization platforms to test different versions of the website and optimize for user behavior.
Next, optimize database queries to minimize server processing times. Pingdom’s server monitoring helps you identify issues that affect server response.
And use a CDN to distribute content globally, minimizing the distance between users and servers. WebPageTest helps simulate performance from multiple global locations to evaluate CDN effectiveness.
Performance optimization is not a one-time task; it requires regular monitoring. Here’s a simple workflow for ongoing audits.
Start by running a comprehensive check using PageSpeed Insights for core issues. Then, follow up with Pingdom and WebPageTest to monitor real-world performance from different locations.
Use a combination of PSI and Chrome DevTools to address high-impact issues like large render-blocking resources and unoptimized images.
And for ongoing monitoring, set up Pingdom for real-time performance monitoring and alerts for critical issues like downtime or sudden spikes in response time. Schedule monthly tests to ensure your site continues performing well, especially after making content or structural changes.
If all you're doing is pasting your client’s homepage URL into PageSpeed Insights, you're probably going to wind up focusing too hard on the wrong things. And that's time you aren't spending getting to the bottom of what's really holding your website back.
A comprehensive performance strategy involves using multiple tools in tandem, each with a specific focus area. By using the combination of tools I've mentioned above (and setting up an ongoing audit workflow), you can identify and fix issues and deliver a better experience to your client’s end users.
