HTTP/3 Test

About HTTP/3 Testing Tool

Ready for HTTP/3?

HTTP/3 or H3 is the upcoming HTTP (Hypertext Transport Protocol) version that leverages QUIC.

QUIC (Quick UDP Internet Connections) - as you can guess by the abbreviation, is a UDP-based protocol built considering the next-generation internet. Ensuring the website or web application loads faster across every device from everywhere is challenging, and H3 aims to help with that.

Once you have enabled H3 on your site, you can quickly use the Domsignal H3 testing tool to determine its status. This tool is powered by cURL to connect using HTTP3 and shows the supported versions.

It's still in the draft, so expect limited server and client support.

Why HTTP/3?

While HTTP/2 was a major successful upgrade over HTTP/1.1, you may ask--why do we keep updating it?

The thing is, with HTTP/2, a single packet loss in the TCP connection blocks the complete data stream (Head-of-line-blocking). That was indeed worse than what we had with HTTP/1.1. So we now have an update (HTTP/3) to improve upon this. Consequently, a network interruption will be limited to that specific stream.

In addition, H3 comes with 0-RTT, zero roundtrip time. This means for reconnections, the client and servers can avoid TLS handshake, decreasing the network latency.