Single-Page Application

A single-page application (SPA) is a web app that, instead of reloading the page on each navigation, swaps content dynamically with JavaScript and changes the URL without a full reload.

The SPA model gives a smooth, app-like experience because there is no jump and reload between pages, but that same feature breaks traditional measurement models. Classic page-based analytics is built on the page-load event; in an SPA this event fires only once at the start and later navigations have no fresh load, so if you do nothing, a user's whole session counts as just one pageview and the pages report stays nearly empty. The solution is the “virtual pageview”: the script must detect the internal route change and record a view manually. Performance metrics also behave differently; slowness in an SPA often happens not in the initial load but in responsiveness to interaction and dynamic rendering, so metrics like INP matter more than the initial load time.