Core Web Vitals are important metrics from Google that measure the performance of websites from the user's point of view. If you are building websites or web apps, you should pay attention to these three key metrics:

1. Largest Contentful Paint (LCP) – This measures how long it takes for the largest element on the page, such as an image or text block, to load. A good LCP should be under 2.5 seconds. If it takes too long, users may lose patience and leave. To learn more about optimizing images for faster loading, check out my article on image formats.

2. Interaction to Next Paint (INP) – This metric measures how quickly a page responds to user interactions, like clicking a button or typing in a form. INP is better than the old metric, First Input Delay (FID), because it looks at all interactions, not just the first one. INP became a Core Web Vital in 2024, replacing FID to give developers a more complete view of how responsive their site is. A good INP should be under 200 milliseconds. Slow responses can frustrate users.

3. Cumulative Layout Shift (CLS) – This tracks how stable the layout of the page is while loading. If things move around on the page unexpectedly, it can be annoying for users. CLS should be under 0.1.

📈 Why Is This Important?

Google uses these metrics as part of its ranking system. This means that if your website meets the Core Web Vitals standards, it can rank higher in search results. Also, faster and more stable websites offer a better user experience, which makes visitors more likely to return.

⚙️ How Can You Improve Core Web Vitals?

1. Optimize Images – Make sure images are compressed and properly optimized for faster loading times. Read more in my article on image formats for websites.

2. Reduce JavaScript Load Time – Heavy or slow JavaScript can delay responses to user actions. For general performance tips, see my article on frontend performance optimization.

3. Use Caching – Storing parts of your website in the browser’s cache can make it load faster when users visit again.

4. Use Modern Technologies – For example, use lazy loading for images and videos, so they load only when needed.

🛠️ Best Tools to Measure Core Web Vitals

Here are some popular tools you can use to measure and monitor Core Web Vitals:

1. Google PageSpeed Insights – This tool provides detailed Core Web Vitals scores for any URL. It also gives suggestions on how to improve performance.

2. Lighthouse – Integrated into Chrome DevTools, Lighthouse provides in-depth reports on a site’s performance, including Core Web Vitals. It’s great for testing during development.

3. Web Vitals Extension – A Chrome extension that gives real-time feedback on Core Web Vitals while you browse.

4. Google Search Console – This tool lets you monitor Core Web Vitals for your entire site and see how individual pages perform over time.

5. Chrome DevTools Performance Panel – This lets you dive deep into the details of how your site is performing, including visualizing LCP, INP, and CLS events.

💡 Conclusion

Core Web Vitals are not just technical details for developers – they affect real user experiences. It’s important to make sure your website not only looks good but also runs fast and stays stable. Optimizing for Core Web Vitals can improve both your website's performance and its ranking in search engines. With the right tools, you can easily track and improve these key metrics to deliver a better user experience.