HTTP/3

HTTP/3 is the third major version of the Hypertext Transfer Protocol, built on QUIC rather than TCP. QUIC provides multiplexed connections over UDP, eliminating head-of-line blocking and reducing connection establishment to a single round-trip. HTTP/3 can also resume an earlier connection without waiting for a round-trip, and its connection migration lets a session survive a change of network, which matters for mobile users switching between Wi-Fi and cellular. That early send comes with a constraint: data carried before the handshake completes can be replayed, so RFC 8470 permits it only for safe methods such as GET and forbids it for unsafe ones. For URL shortening services, what HTTP/3 saves is mostly the setup that precedes the redirect: there is no separate TCP three-way handshake ahead of the TLS exchange, so the time saved depends on the round-trip time between the visitor and the server. Connection migration also means a request issued while the user moves between networks does not necessarily have to be retried.