# RSC Caching Rebask caches server-rendered React Server Components (RSC) payloads separately from page HTML. These payloads power navigations, prefetches, and page updates, while the client uses them to update or populate its [route segment cache](./segment-caching.md). ## How RSC caching works RSC caching lets Rebask reuse a rendered server component payload instead of rendering it again for every cacheable RSC request. The cache serves page and layout payloads for navigations, prefetches, and page updates, separately from page HTML. ::rsc-cache-flow :: An RSC response can contain the full payload or a complete or partial shell. A partial shell is the static prefix of the payload and the tail is the dynamic rest. A complete shell contains the whole payload. ::rsc-payload-shapes :: ## RSC shells Full payloads use the cache key `pr::`. Shells use separate keys: - Shared: `ps::`, reused across parameter values. - Individual page: `ps:::`, tied to one pathname. Shells have their own cache lifetimes and tags. When the client has a partial shell, Rebask re-renders the segment for the tail and checks that the static prefix still matches. If it does not, Rebask returns the full payload instead. The tail response is rendered for each request and is not added to the RSC cache. Unlike the HTML page shells in [Page Caching](./page-caching.md), RSC shells fill the client segment cache and supply tails for navigations rather than resuming a document. See [Segment Caching](./segment-caching.md#shells-and-tails) for how the client stores and reuses them. ## RSC cache lifetimes and invalidation Rebask looks up an RSC entry before rendering a payload. A fresh entry returns `HIT`, a stale entry can be served as `STALE` and Rebask schedules a background revalidation. On a `MISS`, Rebask renders the payload and writes it to the cache when the render is cacheable. Uncacheable renders, including those that read request I/O, are still returned to the client but are not written to the server RSC cache. See [Cache Lifetimes](./cache-lifetimes.md) for the concepts and APIs. See [Cache Handler](./cache-handler.md) to configure a custom server cache storage implementation.