Access-Control-Expose-Headers response header allows a server to indicate which response headers should be made available to scripts running in the browser, in response to a cross-origin request.
Only the CORS-safelisted response headers are exposed by default. For clients to be able to access other headers, the server must list them using the
|Header type||Response header|
|Forbidden header name||no|
Access-Control-Expose-Headers: [<header-name>[, <header-name>]*] Access-Control-Expose-Headers: *
The value "
*" only counts as a special wildcard value for requests without credentials (requests without HTTP cookies or HTTP authentication information). In requests with credentials, it is treated as the literal header name "
*" without special semantics. Note that the
Authorizationheader can't be wildcarded and always needs to be listed explicitly.
The CORS-safelisted response headers are:
Pragma. To expose a non-CORS-safelisted response header, you can specify:
To additionally expose a custom header, like
X-Kuma-Revision, you can specify multiple headers separated by a comma:
Access-Control-Expose-Headers: Content-Encoding, X-Kuma-Revision
For requests without credentials, a server can also respond with a wildcard value:
However, this won't wildcard the
Authorization header, so if you need to expose that, you will need to list it explicitly:
Access-Control-Expose-Headers: *, Authorization
|Fetch Standard (Fetch)|
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