Fullstack react frameworks aren't purely SSR - they're isomorphic JS apps, which can render an initial page load serverside, then use clientside routing, suspen

Fullstack react frameworks aren't purely SSR - they're isomorphic JS apps, which can render an initial page load serverside, then use clientside routing, suspense, serverside components, and clientside rehydration to progressively update the DOM without a full page refresh. They are basically delivered as SPAs, with an integrated, isomorphic backend-for-frontend service embedded in the origin server. They just don't feel like SPAs, because they have a multipage (routing) framework, and isomorphic rendering means those paths can be directly loaded from the server - while any subsequent navigation just updates your UI clientside. In the case of static conteent-based sites, that SSR can even be done ahead of time, as a static built-time render, and the pieces of data needed to load different pieces of content into the SPA ('pages') get dumped out as static JSON resources. That's what Gatsby offers particularly as its specialty versus next.js.