web dev//rendering//SPA

An SPA (single-page application) is a web application where most navigations happen without reloading a complete HTML document. It looks as if the reader changes pages, but the reader stays inside the same application.

An SPA (single-page application) is a web application where most navigations happen without reloading a complete HTML document. It looks as if the reader changes pages, but the reader stays inside the same application.

Its opposite is the MPA, where every click loads a fresh document from the server.

Routing happens in the browser: the URL changes, JavaScript swaps the view, and the document never reloads. This site is one: the same shell serves every route.

SPA is not the same as CSR. One is about navigation, the other about where HTML is built. An SPA can run with CSR (empty shell, everything client-built) or with SSR plus hydration (server-rendered first load, client navigation afterwards).

For crawlers the SPA problem is really the CSR problem: a non-rendering crawler sees the empty shell, and internal links that exist only after JavaScript runs are never followed, which is why a sitemap matters more for SPAs.