Cloudflare is almost as vital to the internet as HTTP itself, providing protection from DDoS and other forms of attacks to a significant part of the internet. Now, their customers can toggle on HTTP/3 support from their dashboard, and any visitors to their sites will automatically be upgraded to HTTP/3 if their browser supports it.
That’s not likely to happen overnight however. Only Google’s Chrome Canary (pre-beta version) has full-fledged support for it and Mozilla believes HTTP/3 will be working in Firefox Nightly before the end of fall.
Now, HTTP/3 is a big deal. It’s the third major change to the language every website uses to communicate since the web was born thirty years ago.
TCP was designed in the 70s as a universal communication standard, though no one at the time expected it would be used for instantaneous communication like it is now. While it contains a lot of code unnecessary for use by most of the internet, it contains three golden features: reliability, the capacity to check for lost data; order, the ability to put mixed-up packages into the order they were sent; and error-checking, the power to check for corrupted data. HTTP/2 employs a restructured TCP and is now used by about 40% of the internet.
HTTP/3 ditches TCP for the Google-developed QUIC (Quick UDP Internet Protocol). QUIC is built on UDP (user datagram protocol), which trades TCP’s reliability and order functions for an increase in simplicity and speed. Fortunately, however, Google’s engineers were able to add back the essentials in creating QUIC, while keeping the speed benefits. It’s also more secure and retains support for TLS (transport layer security).
HTTP/3 is presently used by 3% of websites according to w3techs but expect that number to rise rapidly with Cloudflare and Google on its side.