Send email using Go (Golang) via GMail with net/smtp

smtp-gmail-send.go

package main

import (
	"log"
	"net/smtp"
)

func main() {
	send("hello there")
}

func send(body string) {
	from := "[email protected]"
	pass := "..."
	to := "[email protected]"

	msg := "From: " + from + "\n" +
		"To: " + to + "\n" +
		"Subject: Hello there\n\n" +
		body

	err := smtp.SendMail("smtp.gmail.com:587",
		smtp.PlainAuth("", from, pass, "smtp.gmail.com"),
		from, []string{to}, []byte(msg))

	if err != nil {
		log.Printf("smtp error: %s", err)
		return
	}
	
	log.Print("sent, visit http://foobarbazz.mailinator.com")
}

Enabling "less secure apps" didn't work for me, I kept getting a Error when sending mail: 535 5.7.8 Username and Password not accepted. Learn more at 5.7.8 https://support.google.com/mail/?p=BadCredentials y19sm6477535pfe.9 - gsmtp even though that was definitely my username and password.

What did was turning turning on 2FA and generating an app password instead. The app password can be used in lieu of your actual gmail password anywhere where your password is required.

Thanks brother, this worked for me (replacing password for app password).

Hi @luizuatanabe. The same thing happens to me. Due to Google's policy change in May 2022, it is now no longer possible to disable the "less secure apps" option. Do you know if there is a way to perform this validation to send emails?

@parkare same thing here. Did you figure out a solution?

The "less secure apps" is available for google enterprise accounts.

https://gist.github.com/jpillora/cb46d183eca0710d909a?permalink_comment_id=3519541#gistcomment-3519541

This worked! Instead of password generate a app password and use it as password. Works like charm!!

upd: this work for me, need add parametr from in msg object
msg := []byte("From: ***@mail.com\r\n" +
"To: ***@gmail.com\r\n" +
"Subject: New Hack\r\n" +
"\r\n" +
"Wonderful solution\r\n")