Referer header
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 Referer request header contains the absolute or partial address from which a resource has been requested.
The Referer header allows a server to identify referring pages that people are visiting from or where requested resources are being used.
This data can be used for analytics, logging, optimized caching, and more.
When you click a link, the Referer contains the address of the page that includes the link.
When you make resource requests to another domain, the Referer contains the address of the page that uses the requested resource.
The Referer header can contain an origin, path, and querystring, and may not contain URL fragments (i.e., #section) or username:password information.
The request's referrer policy defines the data that can be included. See Referrer-Policy for more information and examples.
The Referer should also be sent in requests following a Refresh response (or equivalent <meta http-equiv="refresh" content="...">) that causes a navigation to a new page, if permitted by the referrer policy.
Note: The header name "referer" is actually a misspelling of the word "referrer". See HTTP referer on Wikipedia for more details.
Warning: This header may have undesirable consequences for user security and privacy. See Referer header: privacy and security concerns for more information and mitigation hints.
| Header type | Request header |
|---|---|
| Forbidden request header | Yes |
Syntax
Referer: <url>
Directives
<url>-
An absolute or partial address of the web page that makes the request. URL fragments (i.e.,
#section) and user info (i.e.,username:passwordinhttps://username:password@example.com/foo/bar/) are not included. Origin, path, and query string may be included, depending on the referrer policy.
Examples
Referer: https://developer.mozilla.org/en-US/docs/Web/JavaScript
Referer: https://example.com/page?q=123
Referer: https://example.com/
Specifications
| Specification |
|---|
| HTTP Semantics # field.referer |
Browser compatibility
| desktop | mobile | |||||||||||
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Referer
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Length limited to 4096 bytes
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