Cloudflare Measures Origin TLS Preferences, Cutting Handshake Retries from 52% to 3.7%

TLS 1.3 makes the client guess your key exchange before the server says a word, and a wrong guess costs a full extra round trip. Cloudflare stopped assuming and started measuring what each origin actually prefers: HelloRetryRequests fell from roughly 52% to 3.7%, and p90 handshake latency dropped by more than 150 ms. Nothing exotic here — just per-origin measurement beating a clever global default, which is usually how these wins go.