HTTP/2

HTTP/2 is a major revision of the HTTP protocol — first standardized as RFC 7540 and now maintained as RFC 9113 — that keeps HTTP’s familiar semantics while overhauling how bytes move across the wire. Growing out of Google’s SPDY work, it was designed to cut the latency that plagued HTTP/1.1 by letting many requests and responses share a single connection at once.

• Multiplexing - Many concurrent requests and responses flow over one connection, eliminating head-of-line blocking at the HTTP layer.
• Header compression - HPACK compresses repetitive request and response headers instead of resending them in full.
• Binary framing - A binary protocol replaces HTTP/1.1’s plain-text messages, making parsing faster and less ambiguous.
• Server push - Servers can proactively send resources a client is likely to need (now deprecated in practice, but part of the original design).

In real API operations, HTTP/2 is the transport that makes high-throughput, low-latency APIs practical — it is the foundation gRPC is built on, using HTTP/2 framing and headers to carry streaming, multiplexed RPC calls. For anyone delivering large or chatty API responses, moving to HTTP/2 is one of the cheapest performance wins available, and its multiplexing is a big part of why streaming and bidirectional patterns became viable over ordinary HTTP.