HTTP/3 runs over QUIC instead of TCP, which changes how connections establish and how they behave under packet loss. The theoretical benefits are well documented, but the real question for choosing a host is whether HTTP/3 support at the server level actually translates into a measurable speed difference for a typical WordPress or web app deployment. Here's what changes, what doesn't, and how to test it on your own hosting stack.
What Actually Differs Between HTTP/2 and HTTP/3
| Factor | HTTP/2 | HTTP/3 |
|---|---|---|
| Transport | TCP | UDP (via QUIC) |
| Connection setup | TCP handshake + TLS handshake (2 round trips minimum) | Combined QUIC+TLS handshake (1 round trip, 0 on repeat connections) |
| Head-of-line blocking | Present at the TCP layer if a packet is lost | Eliminated — each stream is independent |
| Connection migration | Breaks if client IP changes (e.g. wifi to mobile) | Survives IP changes via connection IDs |
The connection-setup savings matter most on high-latency or lossy connec