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 Authorization header with a secret
  • Case 2: Include a _vercel_no_cache cookie 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.