How We Measure HTTP Timing: DNS, TCP, TLS, TTFB Breakdown

Wed, 25 Feb 2026 00:00:00 +0000

When you check a website’s response time, “847ms” doesn’t tell you much. Is it slow DNS? Network latency? The server itself? You need a breakdown.

At upsonar.io we show exactly where the time goes. Here’s how we do it with Go’s net/http/httptrace package.

The problem

start := time.Now()
resp, _ := http.Get("https://example.com")
fmt.Println(time.Since(start)) // 847ms

847ms. But why? Could be anything.

httptrace hooks into every phase of an HTTP request. You attach callbacks, and they fire as each phase completes: