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|International standard||Hypertext Transfer Protocol Version 3 (HTTP/3) (draft)|
|Introduced||Internet-Draft as of July 2020[update]|
HTTP/3 uses the same semantics as HTTP/1.1 and HTTP/2 (the same operations like GET and POST) and same response codes (like 200 or 404) but uses a different transport protocol aware of these semantics and capable of recovering from packet loss with minimal performance loss. HTTP/3 is developed to fix the major problem of HTTP/2 called "head-of-line blocking" that arises from reliance on TCP: because the parallel nature of HTTP/2's multiplexing is not visible to TCP's loss recovery mechanisms, a lost or reordered packet causes all active transactions to experience a stall regardless of whether that transaction was impacted by the lost packet.
As of July 2020[update], HTTP/3 protocol is an Internet-Draft and has multiple implementations, and according to W3Techs 6.3% of the top 10 million websites support HTTP/3. Stable versions of Firefox and Chrome support HTTP/3 in its current form, but have it disabled by default. Safari 14 will ship with HTTP/3 enabled by default.