http status code
425 Too Early
The HTTP 425 Too Early client error response status code indicates that the server was unwilling to risk processing a request that might be replayed to avoid potential replay attacks.
If a client has interacted with a server recently, early data (also known as zero round-trip time (0-RTT) data) allows the client to send data to a server in the first round trip of a connection, without waiting for the TLS handshake to complete.
A client that sends a request in early data does not need to include the Early-Data header.
See Early-Data for more information.
Status
425 Too Early
Specifications
SpecificationsStandards references are available on the canonical MDN page.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.