SMTP

The settings

Make the key under API keys in the dashboard. The From address must be at a domain verified on the account, as for the API. New accounts start in the sandbox, sending only to their own team until we have approved them.

In your framework

Our tests send with Nodemailer. The others are each framework’s usual SMTP settings with ours filled in.

import nodemailer from 'nodemailer'

const transporter = nodemailer.createTransport({
  host: 'smtp.mydomainshub.com',
  port: 465,
  secure: true,
  auth: { user: 'mydomainshub', pass: process.env.MDH_API_KEY },
})

await transporter.sendMail({
  from: 'Acme <receipts@acme.ng>',
  to: 'ada@example.com',
  subject: 'Your receipt',
  html: '<p>Thanks for your order.</p>',
})

MAIL_MAILER=smtp
MAIL_SCHEME=smtps
MAIL_HOST=smtp.mydomainshub.com
MAIL_PORT=465
MAIL_USERNAME=mydomainshub
MAIL_PASSWORD=mdh_live_…
MAIL_FROM_ADDRESS=receipts@acme.ng
# Laravel 10 and earlier: MAIL_ENCRYPTION=ssl instead of MAIL_SCHEME

EMAIL_HOST = 'smtp.mydomainshub.com'
EMAIL_PORT = 465
EMAIL_USE_SSL = True
EMAIL_HOST_USER = 'mydomainshub'
EMAIL_HOST_PASSWORD = os.environ['MDH_API_KEY']
DEFAULT_FROM_EMAIL = 'Acme <receipts@acme.ng>'

$mail->isSMTP();
$mail->Host = 'smtp.mydomainshub.com';
$mail->Port = 465;
$mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;
$mail->SMTPAuth = true;
$mail->Username = 'mydomainshub';
$mail->Password = getenv('MDH_API_KEY');

WordPress: in a plugin such as WP Mail SMTP, choose “Other SMTP”, then enter the host, SSL encryption, port 465, authentication on, and the username and password above.

What is carried

• Recipients are those your program names in RCPT TO, as SMTP always has. Those in the To and Cc headers keep their place and name; anyone else is Bcc. At least one must be in To, and at most 50 in all.
• From, Reply-To, the subject, the HTML and text, and every attachment. An image the HTML shows with cid: stays inline.
• Headers the API takes: X-* (not X-SES-*), List-Unsubscribe, List-Unsubscribe-Post, List-Id, In-Reply-To, References and Auto-Submitted, at most 20. Others your program adds, such as Message-ID and Date, are ours to write and are left out.
• Sent twice by mistake? The same Message-ID to the same recipients within 24 hours is queued once — so a program that retries after a lost answer does not send it twice.

Tags and scheduling are API-only: SMTP has no place for them. See the API reference.

Limits

• 7 MB a message, attachments included, and 100 emails a connection.
• Your plan’s caps, the sandbox and your suppression list apply as they do to the API, and each email counts against the key’s rate limit as one request does. See the limits.

The replies

A 4xx reply means try again later; a 5xx means something must change first. The text says which rule refused it, in the words the API uses.