• Home Blog LCP and INP are now Baseline Newly availableStay organized with collectionsSave and categorize content based on your preferences. • Barry PollardXGitHubMastodonBlueskyHomepageMichal MocnyXGitHubBluesky Published: December 17, 2025 Published: December 17, 2025 With the release of Safari 26.2 on December 12th, web performance got a fantastic end of year gift withLargest Contentful Paint (LCP)andInteraction to Next Paint (INP)becoming Baseline Newly available as the latest version of all major browsers now include theLargest Contentful Paint APIandEvent Timing APIneeded to measure these metrics. • This was part of theInterop 2025 project, and it’s great to see these delivered this year! • What this means TheCore Web Vitalshave become a widely adopted standard for measuring web page experience both for web developers and with business stakeholders. • They attempt to summarize the complex story of web performance into a number of key measures of how fast a page loads (LCP), how quickly it responds to interactions (INP), and how stable its contents are (CLS). • For a long time, these were only measurable in Chromium-based browsers such as Chrome and Edge.
Article Summaries:
- Safari 26.2, released December 12, 2025, brings Largest Contentful Paint (LCP) and Interaction to Next Paint (INP) metrics to baseline status across all major browsers. The update, part of the Interop 2025 project, adds the required Largest Contentful Paint API and Event Timing API, enabling consistent measurement of Core Web Vitals on Chrome, Edge, Safari, and others. Previously, LCP and INP were only available in Chromium‑based browsers, leaving iOS users without data and creating a performance blind spot. While CrUX data remains Chrome‑only, Real‑User Monitoring tools can now capture these metrics across browsers, improving site performance insights.
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