This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The HyperText Transfer Protocol (HTTP) 425 Too Early response status code indicates that the server is unwilling to risk processing a request that might be replayed, which creates the potential for a replay attack.


425 Too Early


Specification Title
RFC 8470, section 5.2: 425: Early Data Using Early Data in HTTP

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome ? Edge ? Firefox Full support 58IE ? Opera ? Safari ? WebView Android ? Chrome Android ? Edge Mobile ? Firefox Android Full support 58Opera Android ? Safari iOS ? Samsung Internet Android ?


Full support  
Full support
Compatibility unknown  
Compatibility unknown

Document Tags and Contributors

Contributors to this page: chrisdavidmills, mfuji09
Last updated by: chrisdavidmills,