Access-Control-Expose-Headers

The Access-Control-Expose-Headers response header indicates which headers can be exposed as part of the response by listing their names.

By default, only the 6 simple response headers are exposed:

• Cache-Control
• Content-Language
• Content-Type
• Expires
• Last-Modified
• Pragma

If you want clients to be able to access other headers, you have to 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>, ...

Directives

<header-name>

A list of exposed headers consisting of zero or more header names other than the simple response headers that the resource might use and can be exposed.

Examples

To expose a non-simple response header, you can specify:

Access-Control-Expose-Headers: Content-Length

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

Access-Control-Expose-Headers: Content-Length, X-Kuma-Revision

Specifications

Specification	Status	Comment
Fetch The definition of 'Access-Control-Expose-Headers' in that specification.	Living Standard

Browser compatibility

Compatibility notes

• The wildcard value (*) that is mentioned in the latest specification, is not yet implemented in browsers:
  • Chromium: Issue 615313
  • Firefox: bug 1309358
  • Servo: Issue 13283

See also

• Access-Control-Allow-Headers
• Access-Control-Allow-Origin