Request negotiation · Request header
Referer
The URL of the previous page that led to this request.
What is Referer?
Sent by browsers on subresource and navigation requests to inform the target where the request came from. The header is deliberately misspelled — RFC 1945 typo, kept for backwards compatibility.
Typical usage
Read for analytics, anti-CSRF checks, and abuse detection.
Examples
Referer: https://google.com/search?q=devkitsCommon gotchas
Referer is redacted or omitted based on Referrer-Policy. Don't rely on it for security decisions.
Specification
RFC 9110 §10.1.3
Frequently asked questions
What is the Referer HTTP header?
Sent by browsers on subresource and navigation requests to inform the target where the request came from. The header is deliberately misspelled — RFC 1945 typo, kept for backwards compatibility.
Is Referer a request or response header?
Referer is a request header — the client sends it to the server. Read for analytics, anti-CSRF checks, and abuse detection.
What does a Referer header look like?
A typical Referer header looks like: Referer: https://google.com/search?q=devkits.
What are common mistakes with Referer?
Referer is redacted or omitted based on Referrer-Policy. Don't rely on it for security decisions.
Related headers
Referrer-Policy
Controls the Referer header sent on outgoing links and requests.
Accept
Which media types the client can process.
Accept-Encoding
Which content encodings (compressions) the client accepts.
Accept-Language
Preferred human languages for the response.
User-Agent
The client software identifying itself.
Host
The requested host name and port.