Access-Control-Expose-Headers

The 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 Access-Control-Expose-Headers header.

Header type Response header
Forbidden header name no

Syntax

Access-Control-Expose-Headers: <header-name>, <header-name>, ...
Access-Control-Expose-Headers: *

Directives

<header-name>
A list of zero or more comma-separated header names that clients are allowed to access from a response. These are in addition to the CORS-safelisted response headers.
* (wildcard)
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 Authorization header can't be wildcarded and always needs to be listed explicitly.

Examples

The CORS-safelisted response headers are: Cache-Control, Content-Language, Content-Length, Content-Type, Expires, Last-Modified, Pragma. To expose a non-CORS-safelisted response header, you can specify:

Access-Control-Expose-Headers: Content-Encoding

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:

Access-Control-Expose-Headers: *

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

Specifications

Specification
Fetch Standard (Fetch)
# http-access-control-expose-headers

Browser compatibility

BCD tables only load in the browser

See also