Software Engineering
16 Sep 2026
6 min read
HTTP 103 Early Hints Separate Speculation From Final Response Semantics
An HTTP server can emit a 103 Early Hints informational response before it has produced the final response. A client may act on suitable fields in that interim message, such as starting a preload named by Link, even though the eventual status code, header fields, and representation are still pending. This creates a deliberate split between speculative work and authoritative response semantics. The interim response can move selected preparation earlier in time, but it cannot stand in for the final response or determine its meaning.