Vary

Lists the request headers that change the response, so caches keep a separate copy for each.

Header name, or pasted headers

Explained

Examples

Example

Vary: Accept-Encoding, Accept-Language

Vary: * or Vary: Cookie makes responses almost uncacheable. A missing Vary: Origin on CORS responses can serve one site’s headers to another.

Defined in RFC 9110 §12.5.5.