HTTP/2

HTTP/2 (originally named HTTP/2.0) is a major revision of the HTTP network protocol used by the World Wide Web. It was derived from the earlier experimental SPDY protocol, originally developed by Google.^[1][2] HTTP/2 was developed by the HTTP Working Group (also called httpbis, where "bis" means "twice") of the Internet Engineering Task Force (IETF).^[3][4][5] HTTP/2 is the first new version of HTTP since HTTP/1.1, which was standardized in RFC 2068 in 1997. The Working Group presented HTTP/2 to the Internet Engineering Steering Group (IESG) for consideration as a Proposed Standard in December 2014,^[6][7] and IESG approved it to publish as Proposed Standard on February 17, 2015 (and was updated in February 2020 in regard to TLS 1.3 and again in June 2022).^[8][9] The initial HTTP/2 specification was published as RFC 7540 on May 14, 2015.^[10]

The standardization effort was supported by Chrome, Opera, Firefox,^[11] Internet Explorer 11, Safari, Amazon Silk, and Edge browsers.^[12] Most major browsers had added HTTP/2 support by the end of 2015.^[13] About 97% of web browsers used have the capability (and 100% of "tracked desktop" web browsers).^[13] As of July 2023^[update], 36% (after topping out at just over 50%) of the top 10 million websites support HTTP/2.^[14]

Its successor is HTTP/3, a major revision that builds on the concepts established by HTTP/2.^{[2][15][13][16]}