Summary
QUIC over UDP — multiplexing without head-of-line blocking, faster handshake (0-RTT with caveats), connection migration. Falls back to HTTP/2. Benefits high-latency/mobile most. Your app still needs good caching and fewer round trips — QUIC doesn't fix chatty APIs.
Code example
// App-level: reduce round trips; HTTP/3 is transport-level
const [config, user] = await Promise.all([
fetch('/api/config').then((r) => r.json()),
fetch('/api/me').then((r) => r.json()),
]);
Key points
- QUIC over UDP — multiplexing without head-of-line blocking, faster handshake (0-RTT with caveats), connection migration.
- Falls back to HTTP/2.
- Benefits high-latency/mobile most.
- Your app still needs good caching and fewer round trips — QUIC doesn't fix chatty APIs.