Fetch Metadata request headers
Supplies request context that servers can use in a resource-isolation policy.
Support in current browsers
Checked against the current browser versions recorded in MDN browser data 8.0.7.
| Browser | Minimum | Outcome | Reason |
|---|---|---|---|
| Chrome | 150 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Edge | 150 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Firefox | 152 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Safari | 26.5 | Not supported | At least one required mapped feature is not available at this browser baseline. |
| Chrome for Android | 150 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Firefox for Android | 152 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Safari on iOS | 26.5 | Not supported | At least one required mapped feature is not available at this browser baseline. |
| Android WebView | 150 | Works | Every required mapped BCD feature is available without a recorded qualification. |
| Samsung Internet | 29.0 | Works | Every required mapped BCD feature is available without a recorded qualification. |
What this feature can and cannot do
Helps protect against
- Cross-site request forgery
- Cross-site resource abuse
Does not guarantee
- Requests from clients that do not send the headers
- Authorisation flaws
- Incorrect server-side policy decisions
What you need before using it
- A server-side policy with explicit fallback behaviour
Fallback to keep in place
Retain CSRF tokens, SameSite cookies, origin checks, and ordinary authorisation controls.