GoKawiilCloudflare's Automatic Key Exchange slashes origin handshake retries to 3.7%
Cloudflare launched Automatic Key Exchange, a feature that probes origin servers to detect which key agreement algorithms they support before committing to one, rather than always guessing X25519 as before. This measurement-based approach reduced HelloRetryRequest occurrences from about 52% to 3.7% and cut roughly 150ms off connection latency at the 90th percentile, while also enabling post-quantum key exchange (X25519MLKEM768) automatically wherever origins support it.