The HTTP Upgrade-Insecure-Requests request header sends a signal to the server expressing the client's preference for an encrypted and authenticated response, and that it can successfully handle the upgrade-insecure-requests CSP directive.
| Header type | Request header |
|---|---|
| Forbidden header name | no |
Upgrade-Insecure-Requests: 1
A client's request signals to the server that it supports the upgrade mechanisms of upgrade-insecure-requests:
GET / HTTP/1.1 Host: example.com Upgrade-Insecure-Requests: 1
The server can now redirect to a secure version of the site. A Vary header can be used so that the site isn't served by caches to clients that don't support the upgrade mechanism.
Location: https://example.com/ Vary: Upgrade-Insecure-Requests
| Specification |
|---|
| Upgrade Insecure Requests # preference |
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
Upgrade-Insecure-Requests |
44 |
17 |
48 |
No |
31 |
10.1 |
44 |
44 |
48 |
32 |
10.3 |
4.0 |
Content-Security-Policyupgrade-insecure-requests directive
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Upgrade-Insecure-Requests