Unicast vs. Anycast for Webhook Ingress: Reducing Handshake Latency

Webhook senders such as Stripe, GitHub, Shopify and Slack deliver events to endpoints worldwide, and each delivery requires DNS, TCP, TLS and HTTP round trips before payload arrives. For distant receivers these handshakes dominate network cost, and publishers enforce tight response windows ranging from one to ten seconds. The article estimates that a TLS 1.3 setup adds roughly 150 ms and TLS 1.2 about 225 ms for a Dublin-to-Virginia path. It argues that handshake delay rarely causes timeouts, which are more often driven by slow application handlers, though it matters for tight limits and cold-connection bursts. The piece contrasts unicast, which routes all senders to one location, with anycast, where BGP steers senders toward a topologically nearby point of presence.