GoKawiilGo 1.27 speeds up HTTP/1 connection reuse by up to 5x
Go's net/http maintainers Nicholas Husin and Damien Neil report that Go 1.27 significantly improves how the standard library reuses HTTP/1 connections. In their benchmark, making 100 sequential requests to index.golang.org dropped from roughly 710 milliseconds on Go 1.26 to about 150 milliseconds on Go 1.27 when forcing HTTP/1.1 via GODEBUG=http2client=0.
GoKawiil's interpretation of the reporting above, not reported fact.
Establishing a fresh connection requires a TCP handshake plus a TLS handshake, which the authors note can total three round trips before any HTTP data is exchanged, so avoiding repeated setup by reusing existing connections could meaningfully cut latency for applications that make many requests to the same host. This change suggests Go programs using HTTP/1 could see large real-world speedups without any code changes, particularly in latency-sensitive or cross-region scenarios.
- Go 1.27 reduces HTTP/1 connection overhead, cutting benchmark time from ~710ms to ~150ms for 100 requests.
- The gain comes from better reuse of existing TCP/TLS connections instead of repeating costly handshakes.
- Applications making repeated HTTP/1 requests to the same host may see notable performance improvements after upgrading.
Source: go.dev — Nicholas Husin, 2026-10-14
Published there as: “Better HTTP/1 connection reuse in Go 1.27”
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