Developers
Backend SMTP Examples
Copy secure SMTP examples for Node.js, Python, PHP, Ruby and Go. Configure TLS, ports and mailbox credentials to send application email through SMTP Zen.
All SMTP Zen mailboxes can send mail through our SMTP cluster. These examples show how to authenticate securely from server-side applications. Replace the placeholders with your own hostname, mailbox, and password.
Connection prerequisites
- Host: whichever hostname you configured (
orion.smtpzen.comor your issuedmail.domain.com). - Port: 465 (implicit TLS) or 587 with STARTTLS.
- Username: the full mailbox address (e.g.
[email protected]). - Password: the mailbox password set in Plan Manager.
- TLS: Required. Disable “self-signed” overrides; our certificates are issued by Let’s Encrypt.
Store credentials in environment variables or secrets managers rather than committing them to source control.
Node.js (Nodemailer)
import nodemailer from 'nodemailer'
const transporter = nodemailer.createTransport({
host: process.env.SMTP_HOST,
port: 465,
secure: true,
auth: {
user: process.env.SMTP_USER,
pass: process.env.SMTP_PASS
}
})
await transporter.sendMail({
from: '[email protected]',
to: '[email protected]',
subject: 'Deployment complete',
text: 'The latest build has been deployed successfully.'
})
Python (smtplib)
import os
import smtplib
from email.message import EmailMessage
msg = EmailMessage()
msg["Subject"] = "Nightly job finished"
msg["From"] = "[email protected]"
msg["To"] = "[email protected]"
msg.set_content("Backup completed without errors.")
with smtplib.SMTP_SSL(os.environ["SMTP_HOST"], 465) as smtp:
smtp.login(os.environ["SMTP_USER"], os.environ["SMTP_PASS"])
smtp.send_message(msg)
PHP (PHPMailer)
<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
$mail = new PHPMailer(true);
$mail->isSMTP();
$mail->Host = getenv('SMTP_HOST');
$mail->Port = 465;
$mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;
$mail->SMTPAuth = true;
$mail->Username = getenv('SMTP_USER');
$mail->Password = getenv('SMTP_PASS');
$mail->setFrom('[email protected]', 'SMTP Zen Bot');
$mail->addAddress('[email protected]');
$mail->Subject = 'Report ready';
$mail->Body = 'Your report is attached.';
$mail->send();
Ruby (Net::SMTP)
require 'net/smtp'
require 'mail'
mail = Mail.new do
from '[email protected]'
to '[email protected]'
subject 'Smoke tests passed'
body 'All checks green.'
end
smtp = Net::SMTP.new(ENV['SMTP_HOST'], 587)
smtp.enable_starttls
smtp.start('smtpzen.com', ENV['SMTP_USER'], ENV['SMTP_PASS'], :login) do |session|
session.send_message(mail.to_s, mail.from.first, mail.to)
end
Go (net/smtp)
package main
import (
"os"
"crypto/tls"
"log"
"net/smtp"
)
func main() {
host := os.Getenv("SMTP_HOST")
user := os.Getenv("SMTP_USER")
pass := os.Getenv("SMTP_PASS")
auth := smtp.PlainAuth("", user, pass, host)
msg := []byte("Subject: Ping\r\n\r\nEverything is running.\r\n")
conn, err := tls.Dial("tcp", host+":465", &tls.Config{ServerName: host})
if err != nil {
log.Fatal(err)
}
client, err := smtp.NewClient(conn, host)
if err != nil {
log.Fatal(err)
}
defer client.Close()
if err := client.Auth(auth); err != nil {
log.Fatal(err)
}
if err := client.Mail(user); err != nil {
log.Fatal(err)
}
if err := client.Rcpt("[email protected]"); err != nil {
log.Fatal(err)
}
w, err := client.Data()
if err != nil {
log.Fatal(err)
}
if _, err := w.Write(msg); err != nil {
log.Fatal(err)
}
w.Close()
client.Quit()
}
When testing locally, run the same examples inside a staging environment to confirm outbound ports are open. If the connection fails, switch between 465 and 587, or check that your firewall allows outgoing SMTP traffic.