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 1974¹), HTTP/3 uses QUIC (officially introduced in 2021), a multiplexed transport protocol built on UDP. 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 faster than with HTTP/1.1 (which, for many websites, is the only HTTP version deployed). As of July 2026, HTTP/3 is supported by more than 95% of major web browsers in use and 40% 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 has implemented the standard since Sept 2024 (16+ supports HTTP/3 for all users, previously it was limited to a subset of users)

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 (officially introduced in 2021), a multiplexed transport protocol built on UDP. 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 faster than with HTTP/1.1 (which, for many websites, is the only HTTP version deployed). As of July 2026, HTTP/3 is supported by more than 95% of major web browsers in use and 40% 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 has implemented the standard since Sept 2024 (16+ supports HTTP/3 for all users, previously it was limited to a subset of users)

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