Sec-Fetch-User

The Sec-Fetch-User fetch metadata request header is only sent for requests initiated by user activation, and its value will always be ?1.

A server can use this header to identify whether a navigation request from a document, iframe, etc., was originated by the user.

The value will always be ?1. When a request is triggered by something other than a user activation, the spec requires browsers to omit the header completely.

If a user clicks on a page link to another page on the same origin, the resulting request would have the following headers:

Sec-Fetch-Dest: document
Sec-Fetch-Mode: navigate
Sec-Fetch-Site: same-origin
Sec-Fetch-User: ?1

• Related headers
  • Sec-Fetch-Dest
  • Sec-Fetch-Mode
  • Sec-Fetch-Site
• Protect your resources from web attacks with Fetch Metadata (web.dev)
• Fetch Metadata Request Headers playground (secmetadata.appspot.com)