TL;DR
strings.Builder is the fastest and takes least memory.
+ is tied in memory but slightly less performant (although much more convenient).
strings.Join is not a bad alternative for arrays.
fmt.Sprintf is trash.
Check the repo in which I share the benchmarks so you can test them too!
Have you ever wondered what the fastest way to concatenate strings is?
Well I did today, so I whipped up a quick benchmark (since a Google search was not yielding me any conclusive results) and as of today, 1st of May 2025, these are the results:
goos: linux
goarch: amd64
pkg: scratchpad-go
cpu: AMD Ryzen 5 5600X 6-Core Processor
BenchmarkConcatStrings_Plus-12 51331621 21.97 ns/op 8 B/op 1 allocs/op
BenchmarkConcatStrings_Sprintf-12 11596424 102.9 ns/op 40 B/op 3 allocs/op
BenchmarkConcatStrings_StringsBuilder-12 64022565 18.46 ns/op 8 B/op 1 allocs/op
BenchmarkConcatStrings_Join-12 42522718 27.70 ns/op 8 B/op 1 allocs/op
BenchmarkConcatStringAndInt_Plus-12 51975021 22.21 ns/op 5 B/op 1 allocs/op
BenchmarkConcatStringAndInt_Sprintf-12 12212780 98.96 ns/op 21 B/op 2 allocs/op
BenchmarkConcatStringAndInt_StringsBuilder-12 56754538 20.43 ns/op 8 B/op 1 allocs/op
BenchmarkConcatStringAndInt_Join-12 38538142 28.96 ns/op 8 B/op 1 allocs/op
