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 requests 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 | Status | Comment |
|---|---|---|
| Upgrade Insecure Requests The definition of 'upgrade-insecure-requests' in that specification. | Candidate Recommendation | Initial definition. |
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 44 | No1 | 48 | No | 31 | ? |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
|---|---|---|---|---|---|---|---|
| Basic support | ? | 44 | No | 48 | ? | 31 | ? |
1. Under consideration for future release.
Content-Security-Policyupgrade-insecure-requests directive
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Upgrade-Insecure-Requests