Core Web Vitals are essential metrics used by Google to evaluate the quality of a user's experience on web pages. They include Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). To ensure the best possible scores in these areas, here are some recommended practices.
Improving Largest Contentful Paint (LCP)
LCP measures the loading performance of the largest content element visible in the viewport. To improve LCP:
- Optimize images and videos. Use modern image formats like WebP, which offer better compression than traditional formats. Consider lazy loading for images and videos not immediately visible.
- Minimize server response times. Improve your server's response by optimizing your server software or switching to a faster hosting service.
- Remove render-blocking resources. Minimize the amount of CSS and JavaScript that blocks rendering, and use asynchronous or deferred loading for non-critical scripts.
Improving First Input Delay (FID)
FID measures the time from when a user first interacts with your page to the time when the browser is able to respond to that interaction. To improve FID:
- Optimize JavaScript execution. Break up long tasks into smaller ones, use Web Workers for executing scripts in the background, and avoid excessive JavaScript.
- Efficiently load third-party scripts. Third-party scripts can slow down your pages. Load them asynchronously or after the main content of the page has loaded.
Improving Cumulative Layout Shift (CLS)
CLS measures the sum total of all individual layout shift scores for every unexpected layout shift that occurs during the entire lifespan of the page. To improve CLS:
- Allocate space for media and text. Ensure images, videos, and ads have reserved spaces to prevent layout shifts as the page loads.
- Avoid unexpected layout shifts. When adding content asynchronously, such as loading ads or AJAX results, make sure you have allocated space to prevent shifting already loaded content.
Additional Factors
- Use HTTPS. Security is key for user trust, and HTTPS is now a standard for the web.
- Mobile-friendliness. Ensure your sites are optimized for mobile devices, which is important not only for users but also for search engines.
- Accessibility. Ensuring your site's accessibility for users with different needs should be a key part of your design.
Remember, optimizing for Core Web Vitals should be an ongoing process. Regularly monitor your site's performance using tools like Google's PageSpeed Insights and Lighthouse to identify areas for improvement and keep your site aligned with best practices.
