How to Build an SMTP Client in Go

Use the net/smtp package to connect to an SMTP server, authenticate, and send an email message.

package main

import (
	"fmt"
	"net/smtp"
)

func main() {
	from := "sender@example.com"
	password := "secret"
	to := []string{"recipient@example.com"}
	msg := []byte("Subject: Test\r\n\r\nThis is a test email.")

	auth := smtp.PlainAuth("", from, password, "smtp.example.com")
	err := smtp.SendMail("smtp.example.com:587", auth, from, to, msg)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println("Email sent successfully")
}

Building an SMTP client in Go connects your program to an email server using the standard Simple Mail Transfer Protocol. It handles the login and message delivery automatically, similar to how your phone sends a text message through a cellular tower. You use this whenever your application needs to send notifications or reports directly to users.