Topic
Definition
Revalidation marks cached data or rendered output stale so a later request obtains a fresh representation.
In simpler words
After a change, tell the cache that its old answer is no longer safe to reuse.
The correct revalidation mechanism depends on which cache contains the stale representation.
A client ticket list cached by TanStack Query should be invalidated through Query after a successful mutation. That marks the corresponding browser resource stale and lets active observers refetch it.
revalidatePath and revalidateTag are Next server-cache mechanisms. They matter only when the affected server-rendered route or tagged fetch is actually using that caching strategy.
onSuccess: (_ticket, variables) => {
queryClient.invalidateQueries({ queryKey: ['tickets'] });
queryClient.invalidateQueries({ queryKey: ['ticket', variables.id] });
}Invalidate the list and detail representation that a completed write made stale.
// Wrong — does not refresh browser Query data
revalidatePath('/tickets');
// Right for a client Query list
queryClient.invalidateQueries({ queryKey: ['tickets'] });Revalidation APIs are scoped to their own cache layer.
Definition
Path revalidation targets rendered output for a route; tag revalidation targets server fetches that share a declared tag.
In simpler words
Tags are useful when several routes depend on the same server-side resource.
Do not add tags before you know which server-rendered resources must refresh together.
A revalidated representation still passes through the same backend authorization rules on its next request.
Live playground
Choose the cache layer that must refresh after a ticket edit.
Query cache: stale
Next revalidatePath/tag is for Next server caches — not Nest auth.
Test
At least 10 questions — mix of concept, syntax, practical, and logic. Score ≥ 80% (enforced by the API) to save progress.
Checking your session…
10 questions · concept 3 · syntax 2 · practical 3 · logic 2