Website performance is no longer just a technical detail; it is influencing user experience, search engine rankings, and conversions. Google has identified a set of metrics, Core Web Vitals, as a way to determine how users experience the performance of a web page. For a business or website owner looking to improve site performance and SEO, it is no longer recommended to optimize Core Web Vitals; it is a necessity.
Core Web Vitals are three different page experience metrics that Google created: the Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). Each of these metrics describes a different way a user will interact with your website and how Google will measure how well your site performs.
Largest Contentful Paint (LCP) measures the period of time from the moment the user requests the main page content to the moment the browser can render the main content. LCP should preferably be in less than 2.5 seconds from the start of the page load. If users are delayed during this time, they will likely bounce and choose another path. Factors influencing LCP include endpoints that produce slow server times, render-blocking JavaScript and CSS, and images that are too large and take too long to load. This often includes using methods such as lazy-loaded images, choosing a fast hosting server, compressing files, and preloading key elements to optimize LCP.
First Input Delay (FID) looks at responsiveness. FID measures the time from the point when the user first interacts with your page, such as clicking a link or tapping a button, to the point the browser can begin responding to the deferred task. A good FID should be less than 100 milliseconds. A long FID is usually the result of JavaScript bloat and/or long blocking tasks on the main thread. To optimize FID, you can minimize JavaScript execution, utilize browser caching, and break up long tasks into smaller tasks that are executed asynchronously.
Cumulative Layout Shift (CLS) is centered around visual stability. It measures how much of your web page's content shifts around while it loads, which can be a positive frustration for a "user" who is trying to expect the movement of buttons, images, and text. Elements that are taking too long to load can damage trust and the user experience. CLS is considered good at .1s or lower. To maintain a good CLS score, always declare size attributes for images and elements of video, never insert content above existing content unless you have no choice, and reserve enough space for ads, embeds, or dynamically loaded content.
Optimizing Core Web Vitals is not only about passing a performance test; it is about how users will ultimately view your website, which affects user satisfaction and conversions. The faster the page loads, the more stable and responsive a website can be, which will encourage users to stay longer and engage, and convert better. For even eCommerce websites, a one-second delay may lead to a drastic loss of sales. The same is true for content websites; when performance is poor, it will likely affect time-on-site, bounce rate, and ultimately, ad revenue.
Before improving Core Web Vitals, you will need to utilize tools like Google PageSpeed Insights, Lighthouse, and Search Console. You can analyze your current scores and provide meaningful opportunities to improve your performance. Performance can vary over time, so it is essential that you monitor regularly, as content may change, new features may be introduced, or you may be using different third-party scripts.
It is important for your developers and designers to collaborate closely. Developers can easily create a badly designed page with tons of scripts that can lead to disgraceful load times with modern frameworks like React, Vue, and Angular, which can be immensely powerful, but if the developer doesn't take the time to be careful, that can also lead to a heavy script and slow page load. There are things you can do to account for heavy scripts by using server-side rendering, using a CDN, etc. Finally, you should always ask yourself if it is possible to code something more efficiently to maintain your beautiful site and keep it blazing fast.
With Google affirming that Core Web Vitals are a ranking factor, websites focused on Vitals can expect to see rankings, visibility, and organic traffic. However, there is more value than just rankings. By optimizing for Core Web Vitals, you are putting the user experience first by offering the user a better, quieter, and faster user experience.
In a digital world with shorter attention spans and higher user expectations, optimization of Core Web Vitals is your opportunity to establish trust, improve retention, and remain competitive. Whether you are an online retailer, blog, or corporate website, these enhancements are an investment in your performance and long-term viability.