HTTP/3 is the upcoming third major version of the Hypertext Transfer Protocol used to exchange binary information on the World Wide Web. HTTP/3 is based on previous RFC draft "Hypertext Transfer Protocol (HTTP) over QUIC". QUIC is an experimental transport layer network protocol initially developed by Google.
On 28 October 2018 in a mailing list discussion, Mark Nottingham, Chair of the IETF HTTP anjd QUIC Working Group, made the official request to rename HTTP-over-QUIC as HTTP/3 to "clearly identify it as another binding of HTTP semantics to the wire protocol ... so people understand its separation from QUIC" and pass its development from the QUIC Working Group to the HTTP Working Group after finalizing and publishing the draft. In the subsequent discussions that followed and stretched over several days, Nottingham's proposal was accepted by fellow IETF members, who in November 2018 gave their official seal of approval that HTTP-over-QUIC become HTTP/3.