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Devii · Backend · 2026-02-08 · 8 min read

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HTTP/3 And QUIC: What Changed After HTTP/1.1 And HTTP/2

Grounded in IETF RFCs: HTTP/2 multiplexing, then HTTP/3 over QUIC-no performance fairy tales, just protocol facts.

**HTTP/1.1** (RFC 9112 semantics, with messaging historically in RFC 7230 series) used sequential request/response on a connection; pipelining existed but saw limited adoption. **HTTP/2** (RFC 9113) added multiplexed streams over one TCP connection, header compression (HPACK), and server push (later deprecated in practice by many deployments).

**HTTP/3** (RFC 9114) maps HTTP semantics onto **QUIC** (RFC 9000), a UDP-based transport with integrated encryption (TLS 1.3 is used with QUIC as specified). Head-of-line blocking at the TCP layer motivated QUIC’s design: lost packets can affect only the streams they belong to, not the whole connection.

Development workflow on multiple displays
Development workflow on multiple displays

Whether HTTP/3 helps *your* app depends on RTT, loss, and CDN support-measure with real RUM and lab tools. This article summarizes published standards; always read the current RFC text and your vendor’s operational guide for edge behavior.