Have you worked with SMTP protocol for sending emails?

In Go, the net/smtp package is often used for sending emails via SMTP. It allows establishing a connection with the SMTP server, authenticating, and sending the email.

Example of sending a simple email:

package main

import (
	"net/smtp"
	"log"
)

func main() {
	from := "sender@example.com"
	password := "password"
	to := []string{"recipient@example.com"}
	smtpHost := "smtp.example.com"
	smtpPort := "587"

	message := []byte("Subject: Test Email\r\n" +
		"\r\n" +
		"This is the body of the email.")

	auth := smtp.PlainAuth("", from, password, smtpHost)

	err := smtp.SendMail(smtpHost+":"+smtpPort, auth, from, to, message)
	if err != nil {
		log.Fatal(err)
	}
}

This example demonstrates connecting to an SMTP server with authentication and sending an email. TLS can be used for security, and the email can be extended with headers and attachments.