Web Vitals is a set of metrics that help developers understand the user experience on a website. These metrics focus on the loading, interactivity, and visual stability of a page, and are designed to help developers identify and optimize the key performance bottlenecks on their site. The metrics are:
- Largest Contentful Paint (LCP): Measures loading performance. It reports the render time of the largest image or text block visible within the viewport.
- First Input Delay (FID): Measures interactivity. It reports the time from when a user first interacts with a page (i.e. when they click a link or button) to the time when the browser is able to respond to that interaction.
- Cumulative Layout Shift (CLS): Measures visual stability. It reports the sum total of all individual layout shift scores for every unexpected layout shift that occurs during the entire lifespan of the page.
These metrics are important for providing a good user experience because they help you to understand how fast your pages load and become interactive, and how stable your layout is. Google has provided a library named web-vitals and it is a JavaScript library that helps you measure these Web Vitals and report them to various analytics providers.
By using these metrics you can get a better understanding of the user experience on your website, and make informed decisions about how to improve performance and stability.
Advantages of web vitals include:
- Improved user experience: Web vitals focus on metrics that are important to the user experience, such as load time and interactivity.
- Easy to measure: Web vitals can be easily measured using built-in browser APIs, making it simple for developers to track and improve performance.
- Search engine optimization: Improving web vitals can positively impact search engine ranking, as search engines use these metrics to evaluate the quality of a website.
Disadvantages of web vitals include:
- Limited scope: Web vitals only measure a subset of performance metrics, and do not provide a complete picture of a website’s performance.
- Complexity: Understanding and optimizing web vitals can be complex and time-consuming, especially for developers without a background in performance optimization.
- Limited browser support: Some web vitals may not be available on all browsers, which can make it difficult to get a consistent measurement of performance across different browsers.
Some key features of web vitals include:
- Speed: Web vitals measure the time it takes for a website to load and become interactive. This includes metrics such as First Contentful Paint (FCP) and Time to Interactive (TTI).
- Responsiveness: Web vitals measure how well a website responds to user input. This includes metrics such as First Input Delay (FID) and Total Blocking Time (TBT).
- Visual stability: Web vitals measure how stable a website’s layout is. This includes metrics such as Cumulative Layout Shift (CLS).
- Cross-browser compatibility: Web vitals can be measured on different browsers to ensure consistent performance across all devices.
- Integration: Web vitals can be integrated with web development tools, such as Lighthouse and Chrome DevTools, for easy analysis and optimization.
- Standardization: Web vitals are an open standard, which means that they are supported by all major browsers and can be easily integrated into any website.
- Continuous measurement: Web vitals are continuously updated with new metrics and best practices, which helps to keep websites up to date with the latest web performance standards.