HTTP/3
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web, complementing the widely-deployed HTTP/1.1 and HTTP/2. Unlike previous versions which relied on the well-established TCP (published in 1974), HTTP/3 uses QUIC, a multiplexed transport protocol built on UDP. On 6 June 2022, IETF published HTTP/3 as a Proposed Standard in RFC 9114.
| International standard | RFC 9114 (HTTP/3 also uses the completed QUIC protocol described in RFC 9000 and related RFCs such as RFC 9001) |
|---|---|
| Developed by | IETF |
| Introduced | June 2022 |
| Website | https://httpwg.org/specs/rfc9114.html |
HTTP/3 uses similar semantics compared to earlier revisions of the protocol, including the same request methods, status codes, and message fields, but encodes them and maintains session state differently. However, partially due to the protocol's adoption of QUIC, HTTP/3 has lower latency and loads more quickly in real-world usage when compared with previous versions: in some cases over four times as fast than with HTTP/1.1 (which, for many websites, is the only HTTP version deployed).
HTTP/3 is (at least partially) supported by 97% of tracked web browser installations (thereof of 98% of "tracked mobile" web browsers), and 29% of the top 10 million websites. It has been supported by Chromium (and derived projects including Google Chrome, Microsoft Edge, Samsung Internet, and Opera) since April 2020 and by Mozilla Firefox since May 2021. Safari 14 implemented the protocol but it remains disabled by default.