tech.nolog.ist

Core Web Vitals are a set of metrics that measure the performance and user experience of a web application. These metrics are designed to provide a consistent and objective measure of the performance of a website and to help web developers and designers optimize their websites for better user experience.

There are three Core Web Vitals:

Largest Contentful Paint (LCP): This measures the time it takes for the largest content element on a page to load. A good LCP score is under 2.5 seconds. To optimize for LCP, you should minimize the size of your pages, optimize your images and other resources for faster loading, and minimize the number of render-blocking resources.
First Input Delay (FID): This measures the time it takes for a web page to become interactive after a user interacts with it. A good FID score is under 100 milliseconds. To optimize for FID, you should minimize the amount of JavaScript code that runs on your page, optimize the loading of your resources, and minimize the use of third-party scripts.
Cumulative Layout Shift (CLS): This measures the stability of a web page as it loads. A good CLS score is under 0.1. To optimize for CLS, you should ensure that all of your page elements have defined sizes, minimize the use of animations, and avoid dynamically injecting content into the page.

Tracking Core Web Vitals is important because they are directly related to the user experience of a web application. A website with good Core Web Vitals scores will load faster, be more responsive, and be more stable, which will lead to a better user experience. On the other hand, a website with poor Core Web Vitals scores will be slower, less responsive, and less stable, which will lead to a worse user experience.

In addition to the direct impact on user experience, Core Web Vitals are also becoming increasingly important for search engine optimization. Google has announced that it will use Core Web Vitals as a ranking factor in its search algorithms, so websites with good Core Web Vitals scores are more likely to rank higher in search results.

To track Core Web Vitals while developing, I use tools like WebPageTest and Lighthouse. These tools will provide you with detailed reports on the performance of your website and will offer suggestions for optimization. Most modern APM tools also provide Core Web Vitals metrics, so you can track these metrics in production as well.

Tracking Core Web Vitals is essential for optimizing the performance and user experience of a web application. By focusing on improving your LCP, FID, and CLS scores, you can create a faster, more responsive, and more stable website that provides a better experience for your users.