React, HTMX, and TanStack/Start
Modern UI frameworks are shifting away from JSON APIs toward server-rendered markup. React Server Components, HTMX, Hotwire, Remix's iframe approach, and TanStack's SPA-on-SSR model all embrace this pattern. HTMX works well for modernizing legacy Jinja+jQuery UIs through incremental rewrites, React Islands handle highly interactive components, and TanStack delivers interactive experiences with fast initial paint. This architectural shift represents a return to hyper-text transfer while maintaining modern interactivity.