Go Simple Mail

The best way to send emails in Go with SMTP Keep Alive and Timeout for Connect and Send.

IMPORTANT This example is for version 2.2.0 and above.

Version 2.1.3 and below use "text/html" and "text/plain" in SetBody and AddAlternative Also 2.0.0 and below go to this doc https://gist.github.com/xhit/54516917473420a8db1b6fff68a21c99

Introduction

Go Simple Mail is a simple and efficient package to send emails. It is well tested and documented.

Go Simple Mail can only send emails using an SMTP server. But the API is flexible and it is easy to implement other methods for sending emails using a local Postfix, an API, etc.

Features

Go Simple Mail supports:

Multiple Attachments with path
Multiple Attachments in base64
Multiple Recipients
Priority
Reply to
Set other sender
Set other from
Embedded images
HTML and text templates
Automatic encoding of special characters
SSL and TLS
Unencrypted connection (not recommended)
Sending multiple emails with the same SMTP connection (Keep Alive or Persistent Connection)
Timeout for connect to a SMTP Server
Timeout for send an email
Return Path
Alternaive Email Body
CC and BCC
Add Custom Headers in Message
Send NOOP, RESET, QUIT and CLOSE to SMTP client

Documentation

https://godoc.org/github.com/xhit/go-simple-mail

Download

go get -u github.com/xhit/go-simple-mail

Usage

package main

import (
	"github.com/xhit/go-simple-mail"
	"log"
)

func main() {

	htmlBody :=
`<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
		<title>Hello Gophers!</title>
	</head>
	<body>
		<p>This is the <b>Go gopher</b>.</p>
		<p><img src="cid:Gopher.png" alt="Go gopher" /></p>
		<p>Image created by Renee French</p>
	</body>
</html>`

	server := mail.NewSMTPClient()
	
	//SMTP Server
	server.Host = "smtp.example.com"
	server.Port = 587
	server.Username = "test@example.com"
	server.Password = "examplepass"
	server.Encryption = mail.EncryptionTLS
	
	//Variable to keep alive connection
	server.KeepAlive = false
	
	//Timeout for connect to SMTP Server
	server.ConnectTimeout = 10 * time.Second
	
	//Timeout for send the data and wait respond
	server.SendTimeout = 10 * time.Second
	
	//SMTP client
	smtpClient,err :=server.Connect()
	
	if err != nil{
		log.Fatal(err)
	}

	//New email simple html with inline and CC
	email := mail.NewMSG()

	email.SetFrom("From Example <nube@example.com>").
		AddTo("xhit@example.com").
		AddCc("otherto@example.com").
		SetSubject("New Go Email")

	email.SetBody(mail.TextHTML, htmlBody)

	email.AddInline("/path/to/image.png", "Gopher.png")

	//Call Send and pass the client
	err = email.Send(smtpClient)

	if err != nil {
		log.Println(err)
	} else {
		log.Println("Email Sent")
	}
}

Send multiple emails in same connection

	//Set your smtpClient struct to keep alive connection
	server.KeepAlive = true

	toList := [3]string{"to1@example1.com", "to3@example2.com", "to4@example3.com"}

	for _, to := range toList {
		//New email simple html with inline and CC
		email := mail.NewMSG()

		email.SetFrom("From Example <nube@example.com>").
			AddTo(to).
			SetSubject("New Go Email")

		email.SetBody(mail.TextHTML, htmlBody)

		email.AddInline("/path/to/image.png", "Gopher.png")

		//Call Send and pass the client
		err = email.Send(smtpClient)

		if err != nil {
			log.Println(err)
		} else {
			log.Println("Email Sent")
		}
	}