2026-10-15

Go 1.27 improves HTTP/1 connection reuse

A small Transport change lets ordinary response-body closing preserve more HTTP/1 connections, reducing needless connection churn without requiring callers to adopt a new pattern.

Go Systems Performance

Logged at IST: 2026-10-15 10:08 IST

What it is: A Go blog article by Nicholas Husin and Damien Neil describing improved HTTP/1 connection reuse in Go 1.27.

Gist: In earlier Go versions, an HTTP/1 connection could be discarded when a caller closed a response body with unread bytes. Go 1.27's net/http.Transport asynchronously drains a limited amount, up to 256 KB or 50 ms, to salvage reuse. The article reports roughly a 5× improvement in its repeated-request benchmark. Callers can keep closing response bodies as usual; HTTP/2 was not affected by this particular issue.

Why it matters: A useful performance improvement hidden behind unchanged, idiomatic Go code: fewer unnecessary connection setups, without asking application code to manage a more complicated lifecycle.

Source: https://go.dev/blog/http-connection-reuse