After Chrome and Cloudflare, Mozilla added HTTP/3 support to the Firefox browser in Nightly version, but the new HTTP protocol isn’t functioning as it has not yet received the support for QUIC Protocol.
We’ve covered Google has added support for Experimental “HTTP over QUIC “support aka HTTP3 to Chrome Canary and can be tested by running Chrome from the command line.
The new protocol, the successor to HTTP2 is developed by Google and will use UDP instead of TCP protocol to send HTTP requests, FYI, QUIC is the short form for “Quick UDP Internet Connections”.
Mozilla has landed HTTP3 support in Firefox 72 Nightly and is disabled by default, but it can be enabled by toggling below said pref value to “true” in about:config, but be warned, this may break some websites and the browser.
a List of demo sites is available to test the feature, but most of the “HTTP/3 test sites” are not loading and Google’s Quic Rocks site in Firefox isn’t displaying “you’ve successfully loaded quic.rocks using QUIC” message when visited.
The Network tab in Firefox dev tools also is showing the browser is using the protocol “HTTP/1.1” where it should be “http/2+Quic/99”, which is actually HTTP3 in disguise said by Google Developer Robin.
Expect Mozilla to announce when the HTTP/3 feature is available for testing in Firefox browser.