How to Set Environment Variables Programmatically in Go

Use os.Setenv to set an environment variable or os.Unsetenv to remove it within your Go program.

package main

import (
	"fmt"
	"os"
)

func main() {
	os.Setenv("MY_VAR", "my_value")
	os.Unsetenv("MY_VAR")
	fmt.Println("Done")
}

For runtime-only debugging settings like GODEBUG, set the GODEBUG environment variable before running the binary using os.Setenv or via the shell.

Setting environment variables programmatically in Go lets your program change its own settings while running. It is like changing a configuration switch in the middle of a game without restarting. You use this when you need to toggle features or debug flags dynamically.