HTTP/3 is the to-become next generation of the HTTP protocol family. This version is similar to HTTP/2 in features, and is most different than its predecessor primarily by the fact that HTTP/3 will only be done over QUIC.

QUIC is a new reliable transport protocol that could be viewed as a sort of next generation TCP.

HTTP/3 explained is a free and open booklet describing the HTTP/3 and QUIC protocols.

Web version: https://http3-explained.haxx.se/en/

source: HN