Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The Early-Data header is set by an intermediary to indicate that the request has been conveyed in TLS early data, and also indicates that the intermediary understands the 425 (Too Early) status code.
The Early-Data header is not set by the originator of the request (i.e., a browser).
| Header type | Request header |
|---|---|
| Forbidden header name | no |
Early-Data: 1
GET /resource HTTP/1.0 Host: example.com Early-Data: 1
| Specification |
|---|
| Using Early Data in HTTP # header |
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
Early-Data |
No |
No |
58 |
No |
No |
No |
No |
No |
58 |
No |
No |
No |
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Early-Data