Google announces Web Vitals, user experience and performance metrics for websites

Google today announced Web Vitals, an initiative to provide web developers and website owners with a unified set of metrics for building websites with user experience and performance in mind. Web Vitals is the set of quality signals that Google believes are “essential to delivering a great user experience on the web.”

Over the years, Google has offered a slew of tools to help business owners, marketers, and developers improve user experiences. The company is now admitting that the sheer number created “its own set of prioritization, clarity, and consistency challenges for many.” In short, Google has realized the information overload was contradictory and confusing. This is an attempt at a reset.

Born online, Google’s revenues are directly tied to the web. The company has a vested interest in improving the web’s user experience. Given Google’s reach, including over 1 billion Chrome users and over 2.5 billion monthly active Android devices, not to mention Google Search, anyone with a website needs to track what Google prioritizes. If you’ve been paying attention to Google’s vision for the web and Chrome releases, some of these metrics will be familiar.

Google wants site owners to gather their own real-user measurement analytics. The company is also launching an open source web vitals JavaScript library and a developer preview of a Core Web Vitals extension. Other browsers have shipped the current Core Web Vitals draft specifications.

Annual updates for Core Web Vitals

Measuring quality of user experience is often site and context specific. Core Web Vitals attempt to spell out what Google considers critical for all web experiences. This year’s Core Web Vitals include loading experience, interactivity, and visual stability of page content. Google says these metrics capture important user-centric outcomes, are field measurable, and have lab diagnostic metric equivalents. Specifically:

• Largest Contentful Paint measures perceived load speed and marks the point in the page load timeline when the page’s main content has likely loaded.
• First Input Delay measures responsiveness and quantifies the experience users feel when trying to first interact with the page.
• Cumulative Layout Shift measures visual stability and quantifies the amount of unexpected layout shift of visible page content.

Next, Google wants to make Core Web Vitals easy to access and measure across its own tools. Chrome UX Report already lets site owners see how real-world Chrome users experience their site. The BigQuery dataset already surfaces publicly accessible histograms for all of the Core Web Vitals. Over the coming months, Google plans to update Lighthouse, Chrome DevTools, PageSpeed Insights, and Search Console’s Speed Report, and also release a new REST API.

Google plans to update Core Web Vitals annually. The company is also promising “regular updates on the future candidates, motivation, and implementation status.” You’ll want to watch web.dev for those.

For 2021, Google is promising “building better understanding and ability to measure page speed, and other critical user experience characteristics.” The company shared a few examples: extending the ability to measure input latency across all interactions, not just the first; new metrics to measure and quantify smoothness; and primitives that will enable delivery of instant and privacy preserving experiences.