Access-Control-Expose-Headers

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The HTTP 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

http
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)

Any header. 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 *.

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:

http
Access-Control-Expose-Headers: Content-Encoding

To additionally expose a custom header, like Kuma-Revision, you can specify multiple headers separated by a comma:

http
Access-Control-Expose-Headers: Content-Encoding, Kuma-Revision

For requests without credentials, a server can also respond with a wildcard value:

http
Access-Control-Expose-Headers: *

A server can also respond with the * value for requests with credentials, but in this case it would refer to a header named *.

Specifications

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

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Access-Control-Expose-Headers
Wildcard (*)

Legend

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Full support
Full support

See also