What tools can you use to assess Core Web Vitals performance?

Story Based Question

You’ve been working hard to optimize your e-commerce website, focusing on improving user experience and SEO. Recently, you read that Core Web Vitals are critical for ranking on Google, but you’re unsure how to assess how your website is performing in this area. What tools can you use to assess Core Web Vitals performance and how can they help you improve your site’s UX and SEO?

Exact Answer

You can use tools like Google PageSpeed Insights, Lighthouse, Search Console, and Web Vitals Extension to assess Core Web Vitals performance. These tools provide detailed insights into metrics like Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS), helping you identify areas for improvement.

Explanation

Core Web Vitals are Google’s set of user experience (UX) metrics that measure how well a website performs in terms of speed, interactivity, and visual stability. These metrics are critical because they affect both user satisfaction and search engine rankings. To track these metrics and optimize your website’s Core Web Vitals performance, you can rely on several free and user-friendly tools.

Let’s break down the tools you can use:

1. Google PageSpeed Insights

• What It Does: PageSpeed Insights gives you performance scores for both mobile and desktop versions of your site. It measures LCP, FID, and CLS, and provides specific recommendations to improve them.
• Why It Matters: This tool is easy to use and gives you a clear picture of how your website is performing in terms of Core Web Vitals.
• Example Connection: For your e-commerce site, you run the homepage through PageSpeed Insights and notice that your LCP is 5 seconds due to a large product image. The tool suggests compressing the image to improve load time and Core Web Vitals.

2. Lighthouse

• What It Does: Lighthouse is a tool built into Chrome’s Developer Tools that runs performance audits on your website. It measures LCP, FID, and CLS along with other metrics like Time to Interactive (TTI) and Total Blocking Time (TBT).
• Why It Matters: It provides detailed insights into why your site might be underperforming, including how specific resources (e.g., JavaScript or images) are impacting Core Web Vitals.
• Example Connection: Running your e-commerce site through Lighthouse could reveal that your homepage takes too long to load because JavaScript is blocking the rendering process. Fixing this can improve FID and LCP scores.

3. Google Search Console (Core Web Vitals Report)

• What It Does: Search Console offers a Core Web Vitals report that aggregates data from real users, showing how your site performs on both mobile and desktop devices in real-world conditions.
• Why It Matters: The data in Search Console is based on real user experiences (called field data), making it an excellent tool for identifying performance issues affecting your audience.
• Example Connection: After checking the Core Web Vitals report, you might find that 50% of users experience poor LCP on mobile due to heavy images. This insight lets you focus on optimizing those images for better performance.

4. Web Vitals Extension

• What It Does: The Web Vitals Extension is a Chrome browser extension that measures Core Web Vitals in real-time as you interact with your website.
• Why It Matters: This tool provides instant feedback on how Core Web Vitals are performing during your site’s interaction, making it helpful for testing specific pages or user interactions.
• Example Connection: You use the Web Vitals Extension to check the performance of your checkout page in real-time. It shows that your CLS is high due to dynamically loaded content. By addressing this layout shift, you can improve the page’s stability for users.

Example

Let’s say you’ve just launched a new promotional page for your jewelry store and want to make sure it meets Google’s Core Web Vitals standards. Here’s how you could use each tool:

1. Google PageSpeed Insights:

• You run the page and see that the LCP is 6 seconds, primarily due to a large product image (3MB). The tool suggests compressing the image and serving it in a next-gen format (e.g., WebP).
• Next Step: You optimize the image, reducing its size to 800KB, and retest the page. The LCP score improves to 2.5 seconds.

2. Lighthouse:

• You run the page through Lighthouse and discover that FID is high (over 200ms), primarily because JavaScript is blocking the main thread.
• Next Step: You implement code-splitting and defer non-essential JavaScript, improving FID to under 100ms.

3. Google Search Console (Core Web Vitals Report):

• The report shows that the mobile version of your site has an LCP issue for the promo page, and 60% of users are experiencing this problem.
• Next Step: You prioritize fixing the image sizes and also optimize your server to respond faster to requests.

4. Web Vitals Extension:

• You use the extension while navigating the site and notice that CLS is 0.35 on the product page, indicating that layout shifts are happening as images load.
• Next Step: You adjust the layout by ensuring all image sizes are defined in the HTML, stabilizing the content as it loads.

After implementing these changes, your e-commerce site now has:

• LCP: 2.5 seconds (optimized images).
• FID: 95ms (deferred JavaScript).
• CLS: 0.05 (stable layout).
• Results: Improved user experience, higher conversion rates, and a boost in SEO rankings due to better Core Web Vitals.

Using tools like Google PageSpeed Insights, Lighthouse, Search Console, and the Web Vitals Extension allows you to effectively measure and improve Core Web Vitals performance. These tools give you the data you need to optimize loading times, interactivity, and visual stability, ensuring a better user experience and improved SEO performance.