What is CSR Shell?
A minimal HTML shell that renders content in the browser after JavaScript loads. Client rendering suits authenticated dashboards behind login, where SEO matters less and interactivity starts only after scripts execute.
Related terms
SSR Per Request
Fresh HTML rendered on the server for every request, used for personalized or frequently changing pages. Server rendering guarantees complete markup on first paint but costs compute per visit, so reserve it for dynamic routes.
Hydration Cost
The JavaScript work that turns server-rendered HTML into an interactive app. Hydration replays component logic in the browser, so oversized bundles delay input readiness even when paint looks instant.
Client-Side Rendering
Building page content in the browser with JavaScript after an initially thin HTML shell. Flexible for apps, but critical content and links should still be server-available for crawlers and fast paint.
SvelteKit adapter-static
A SvelteKit build target that emits a fully static site with no server runtime. Fully static output fits documentation and marketing pages, but any route needing server logic must switch back to a server adapter.
Immutable Hashed Assets
Static files with content hashes in their filenames, emitted under the immutable build output. When code changes the hash changes, so browsers safely cache each version forever without risking stale JavaScript or styles.
Preload & Prefetch
Resource hints that load critical files early or fetch likely-next files during idle time. Preload prioritizes fonts and hero assets for the current page, while prefetch warms the cache for routes the visitor may open next.