HTTP is the language browsers and web servers speak. Its third major version, HTTP/3, was published by the IETF as RFC 9114 in June 2022. Every major browser supports it, and a large share of web traffic already uses it.
What is different
HTTP/1.1 and HTTP/2 run over TCP. HTTP/3 runs over QUIC, a newer transport built on UDP. QUIC brings three practical improvements:
- Faster connection setup. The transport and encryption handshakes are combined, so a secure connection is ready sooner, and returning visitors can often send data immediately.
- No head-of-line blocking. With TCP, one lost packet holds up everything behind it. QUIC streams are independent, so a lost packet only delays the resource it belongs to.
- Connection migration. When a phone moves from Wi-Fi to mobile data, a QUIC connection can continue instead of starting over.
Who benefits most
On a fast, stable office connection, the difference is small. On mobile networks, congested Wi-Fi and long-distance links, where packet loss and changing networks are common, HTTP/3 can noticeably cut load times. For businesses whose customers browse mainly on phones, that is most of the audience.
How to enable it
- Use a web server or CDN that supports HTTP/3. LiteSpeed, recent nginx versions and major CDNs do.
- Make sure UDP port 443 is open in your firewall, alongside TCP 443.
- The server announces HTTP/3 through the Alt-Svc header; browsers switch automatically and fall back to HTTP/2 if UDP is blocked.
- Test with your browser's developer tools to confirm the protocol in use.
How IDX helps
IDX shared and web hosting run on LiteSpeed servers, and LiteSpeed supports HTTP/3. For VPS and dedicated servers, our team can set up HTTP/3 and the firewall rules it needs as part of our managed services.
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