Apple Adds Core Web Vitals to Safari

Apple has rolled out an update to its Safari browser that gives website owners improved visibility into how their sites perform for users. The latest version now allows accurate tracking of two important Core Web Vitals metrics: Largest Contentful Paint (LCP) and Interaction to Next Paint (INP).

This update arrives with Safari version 26.2, which introduces native support for measuring LCP alongside the Event Timing API. The Event Timing API is essential for calculating INP, a metric that reflects how responsive a website feels when users interact with it.

With these additions, site owners can now collect real-world performance data directly from Safari users. This information can be accessed through the browser’s Performance API and analysed using existing analytics tools or real user monitoring platforms.

Both LCP and INP are part of Google’s Core Web Vitals framework, which plays a role in search rankings and overall user experience. LCP focuses on loading performance, while INP measures responsiveness, giving a broader picture of how users experience a site.

LCP tracks how long it takes for the largest visible element on a page to appear within the user’s viewport. This is often a hero image, banner, or a large block of text that dominates the initial view of the page.

INP, on the other hand, measures how quickly a website responds after a user interaction, such as clicking a button, tapping a link, or typing into a form. It records the slowest interaction during a user’s visit, making it a strong indicator of whether a page feels smooth or sluggish.

Until now, Safari did not provide native support for these measurements, which created a long-standing gap in performance data. For websites with a high proportion of Apple device users, this meant an incomplete picture of real user experience.

By enabling these metrics, Safari removes that blind spot and allows site owners to better understand how their sites perform across a wider range of devices and browsers. This is particularly valuable given the popularity of Safari on iPhones, iPads and Macs.

It is important to note that this update does not affect public tools such as PageSpeed Insights or the Chrome User Experience Report (CrUX). These tools rely on Chrome-based data and will continue to function as they do now.

However, websites that have configured their own field data collection can now include Safari users in their performance reporting. This applies to platforms such as Google Analytics and other analytics or monitoring solutions.

Popular analytics tools including Google Analytics (GA4), Adobe Analytics, Matomo, Amplitude and Mixpanel can now be set up to surface LCP and INP data from Safari traffic. Custom or in-house monitoring systems can also take advantage of this update.

In addition, real user monitoring platforms are now able to capture and display this performance data. Services such as Cloudflare Web Analytics, Datadog RUM, New Relic Browser, SpeedCurve and Sentry Performance are among those that can support Safari-based metrics.

According to Apple’s documentation, the Event Timing API measures the full timeline of a user interaction. This includes the initial input, any processing by the website, updates to the page, and the moment the browser renders the result on screen.

This level of detail helps site owners identify interactions that cause delays and understand why certain pages may feel unresponsive. LCP data, meanwhile, provides a clear signal of when a page appears loaded from a user’s perspective.

Overall, Safari 26.2 delivers performance insights that are critical for SEO, usability and ongoing optimisation. As Safari accounts for a significant share of global web traffic, this update enables site owners to gain a more complete and accurate view of real user experience across modern browsers and devices.