HTTP/3 at the edge

Every Easel deployment and domain is now served over HTTP/3, with nothing to turn on. HTTP/3 runs over QUIC, which sets up a connection in fewer round trips than TCP and TLS, and a lost packet doesn’t hold up the other requests on the connection. That matters most on mobile and lossy networks.

How clients switch

Browsers learn that a site supports HTTP/3 from its responses, then use it for their next connections. Clients that reach Easel over IPv6, or whose network blocks UDP, keep using HTTP/2 over TCP as before, so nothing breaks while a client can’t use QUIC.

Updates that don’t drop requests

When Easel updates its edge, each region now moves traffic off a machine before it restarts. HTTP/3 clients are told to open new connections elsewhere, packets for connections already in flight still reach the machine that owns them, and HTTP/1 and HTTP/2 connections finish what they’re doing first.

Before HTTP/3 went live, we ran it through seven rollout scenarios, twice, with zero failed requests over TCP or HTTP/3.