Responses include a header called X-Vercel-Cache that contain details about the state of the cache for the resource. The possible values are shown in the diagrams below.
MISS
MISS: The response was not found in the edge and thus fetched from an origin.
HIT
HIT: The response was served from the edge.
STALE
STALE: The response is stale (served from the edge).
A background request to the origin was made to get a fresh version. (see Stale-While-Revalidate for more info)
BYPASS
BYPASS: The cache was bypassed and so the response was served from an origin.
- Case 1: Include an
Authorizationheader with a secret - Case 2: Include a
_vercel_no_cachecookie header or query param
PRERENDER
PRERENDER: The response was served from static storage.
An example of prerender is in Next.js, when setting fallback:true in getStaticPaths. However, fallback:blocking will not return prerender.
REVALIDATED
REVALIDATED: The response was served from origin and the cache was refreshed due to an authorization from the user in the incoming request.