21CTO

Apr 13, 2026 · Industry Insights

Why HTTP/3 Beats HTTP/2: Unpacking TCP Head‑of‑Line Blocking and QUIC Gains

The article analyzes why HTTP/3, built on QUIC over UDP, can outperform HTTP/2 in lossy or mobile networks by eliminating TCP's head‑of‑line blocking, offering faster handshakes, seamless connection migration, and better congestion control, while also outlining scenarios where HTTP/2 remains preferable.