Monitoring in-page UX in single-page apps (SPAs) has always been spotty. Core Web Vitals and other metrics are based around the concept of full page loads — but, SPAs load once, then swap content dynamically as users "soft" navigate. Everything after that first load has been somewhat invisible.
That changes with soft-navigation attribution, which lets browsers detect when an in-page navigation occurs — making it possible to collect accurate Core Web Vitals for each soft navigation.
Calibre RUM now measures soft navigations automatically, with no additional configuration required. Browser support is currently Chrome 151+, Edge 151+, so bare in mind that current observations will be limited, until browser support improves.
You’ll see Core Web Vitals for your SPA with accurate URL attribution, giving you a much clearer picture of real user experience across your sites and apps.
Filter any RUM report by Soft navigation to see how in-app route changes perform, including subparts and the elements responsible.
Filter any report to see soft navigations on their own, or view by navigation type to compare them against the initial load.
Grouping by Navigation type displays Soft Navigation performance alongside others. (Figures displayed are for demonstration purposes only).
If you already run Calibre RUM, there’s nothing to install or turn on: soft navigations start flowing in automatically.
To learn more, see Filtering RUM reports and the RUM documentation, or read about the evolution of soft navigations in Google Chrome’s Monitoring soft navigations explainer.