String Concatenation vs strings.Builder in Go

Sat, 13 Jun 2026 10:34:19 +0700

I often leave the same comment when I see string concatenation inside a loop:

If you build a string in a loop, use strings.Builder.

That comment sometimes gets pushback from the team: the two operations probably will not matter much. Today, I want to show a simple benchmark to demonstrate why strings.Builder is superior to doing += inside a loop.

The runnable code and raw benchmark output are available in the public repo: gitlab.vvivid.dev/showcase/go-lang-case-study.

Go Language Case Studies

Sat, 13 Jun 2026 00:00:00 +0000

This is where I keep small Go case studies that support the technical writing on this site. Each topic is built as a runnable example with tests or benchmarks, so the discussion can point to code instead of relying only on explanation.

Public repo: gitlab.vvivid.dev/showcase/go-lang-case-study.

The first case study compares normal string concatenation with strings.Builder, including benchmark output and allocation counts.

Benchmarking on Ou David | Systems Engineer

String Concatenation vs strings.Builder in Go

Go Language Case Studies