Chrome is launching a final origin trial for the Soft Navigations API in Chrome 147 (through 149) before its planned full release. The API enables detection and measurement of soft navigations — JavaScript-driven URL updates without full page loads — which are common in Single Page Applications (SPAs). The key motivation is enabling accurate Core Web Vitals measurement (LCP, CLS, INP, FCP) for SPAs, which currently lack browser-level navigation signals. The API introduces two new performance entries: SoftNavigationEntry and InteractionContentfulPaint, both observable via PerformanceObserver. Changes since the last trial include decoupling InteractionContentfulPaint from soft navigations, adding a largestInteractionContentfulPaint attribute, and adding replaceState support. Developers can test via Chrome flags, the origin trial, or Chrome DevTools Performance panel (Chrome 145+). Feedback is requested before the API ships and sites begin depending on it.
Table of contents
What are soft navigations?Need for the Soft Navigation APICore Web Vitals and SPAsHow the API enables measurement of Core Web Vitals for SPAsHow are soft navigations triggered?Help needed to test the Soft Navigation APIWhat has changed since the last origin trialHow to testFeedbackSort: