What Is New in Go 1.21

min, max, slog, and More

Core
2026-04-17T12:05:42+00:00
Go 1.21 adds built-in min/max functions, the log/slog package for structured logging, and GODEBUG for runtime control.

Go 1.21 introduces built-in min and max functions, a structured logging package log/slog, and the GODEBUG environment variable for controlling runtime behavior. Use min and max to replace verbose conditional logic, log/slog for structured logs, and GODEBUG to manage compatibility settings like panicnil.

package main

import (
	"fmt"
	"log/slog"
)

func main() {
	// Built-in min/max
	fmt.Println(min(1, 2)) // 1
	fmt.Println(max(3, 4)) // 4

	// Structured logging
	slog.Info("Starting server", "port", 8080)

	// GODEBUG example (set in environment before running)
	// GODEBUG=panicnil=1 go run main.go
}