Apple Safari Update Enables Tracking Two Core Web Vitals Metrics
Apple’s latest Safari update enables tracking of two Core Web Vitals metrics, improving performance measurement for developers and site owners.
Apple’s latest Safari 26.2 release finally gives site owners native access to two critical Core Web Vitals metrics Largest Contentful Paint (LCP) and Interaction to Next Paint (INP) directly from Safari users. For SEOs and performance teams, that means long‑standing blind spots on Apple traffic can now be filled with real user monitoring data instead of educated guesses.
Native LCP & INP Support In Safari
Safari 26.2 adds support for LCP and the Event Timing API via the browser’s Performance API, enabling accurate collection of both metrics through your own analytics and RUM tooling.
LCP, already a Core Web Vital and ranking signal, measures how long it takes for the largest visible element typically a hero image, main heading, or large text block to appear in the viewport, acting as a strong proxy for when the page “feels loaded” to users.
INP, powered by the Event Timing API, tracks the worst (slowest) interaction during a visit by measuring the full timeline from a user’s click, tap, or keypress through event handlers and DOM updates to the moment the browser paints the result.
It’s a crucial indicator of whether a page feels responsive or “frozen,” and fast INP scores typically correlate with a smoother, less frustrating experience for interactive sessions.
What Changes (And What Doesn’t) For Measurement
This Safari update doesn’t affect Chrome-based public tools like PageSpeed Insights or the Chrome User Experience Report (CrUX), which will continue to rely on Chrome’s field data.
The big change is that Safari users can now be included in your own first‑party field performance datasets such as
- Google Analytics 4
- Adobe Analytics
- Matomo
- Amplitude
- Mixpanel
In-house pipelines whenever you’ve instrumented LCP and INP collection via the Performance API.
Real User Monitoring platforms can also now surface these metrics for Apple traffic. Providers like:
- Akamai mPulse
- Cloudflare Web Analytics
- Datadog RUM
- Dynatrace
- Elastic Observability
- New Relic Browser
- Raygun
- Sentry Performance
- SpeedCurve
- Splunk RUM
That can ingest Safari’s LCP and INP data alongside Chrome and Firefox, giving a much more complete cross‑browser performance picture.
How Apple Describes The New APIs
Apple’s official documentation frames the change very clearly:
“Safari 26.2 adds support for two tools that measure the performance of web applications, Event Timing API and Largest Contentful Paint.“
On the Event Timing API and INP:
“The Event Timing API lets you measure how long it takes for your site to respond to user interactions. When someone clicks a button, types in a field, or taps on a link, the API tracks the full timeline — from the initial input through your event handlers and any DOM updates, all the way to when the browser paints the result on screen. This gives you insight into whether your site feels responsive or sluggish to users. The API reports performance entries for interactions that take longer than a certain threshold, so you can identify which specific events are causing delays. It makes measuring “Interaction to Next Paint” (INP) possible.“
On LCP:
“Largest Contentful Paint (LCP) measures how long it takes for the largest visible element to appear in the viewport during page load… LCP gives you a clear signal about when your page feels loaded to users, even if other resources are still downloading in the background.”
Safari’s Web Inspector also now surfaces LCP entries directly in the Timelines UI, making it easier for developers to correlate LCP timing with other layout and rendering work during debugging.
Why This Matters For SEO And UX Monitoring
Safari users represent a significant share of traffic on many sites, especially on mobile, and until now it’s been difficult to get reliable, first‑party LCP and INP data from that audience. With Safari 26.2, performance and SEO teams can:
- Validate whether Core Web Vitals optimizations are working consistently across Chrome, Firefox and Safari.
- Detect Safari‑specific regressions (for example, slow interactions tied to iOS or WebKit quirks) that previously hid in averages.
- Make more confident decisions about UX trade‑offs, knowing that Apple traffic is no longer a blind spot in RUM dashboards.
From an SEO perspective, this doesn’t change how Google collects Core Web Vitals in CrUX, but it does improve your ability to debug and optimize issues that affect a big slice of your real audience, something that ultimately supports better engagement and, indirectly, stronger performance in search.
