Next.js ~Chache~

In Next.js, there are four layers of caching strategy for performance optimization or cutting costs.

Cache Type	Storage Location	Stored Content	Purpose	Lifetime
Request Memoization	Server	fetch response values	Avoid duplicate requests within a render pass	Per request only
Data Cache	Server	Data	Reuse data across users and deployments	Persistent (revalidatable)
Full Route Cache	Server	HTML / RSC payload	Reduce rendering cost	Persistent (revalidatable)
Router Cache	Client	RSC payload	Reduce requests during client-side navigation	Session-based / time-limited

Next.js 15 introduced use cache directive.

・This is a new mechanism that allows you to declare “cache this output” on a per-function or per-component basis.

・You can intuitively specify the scope of caching without using complex APIs such as the traditional unstable_cache.

・Next.js 16 introduced PPR(Partial Pre Rendering), which enhances the mechanism for delivering content quickly by combining cached static content with dynamic content.

Cache Refresh (Revalidation) There are two main ways to refresh cached data.

Time-based Revalidation: Specify the number of seconds using the next: { revalidate: 60 } option in the fetch request.

On-demand Revalidation: Use revalidatePath or revalidateTag to explicitly invalidate the cache when a data mutation occurs.