SMTP

Prefer SMTP? Point any existing mailer — Nodemailer, Postfix, a framework's mailer, a legacy app — at mailstein and keep your code. Your API key is the password.

Connection settings

Example — Nodemailer

import nodemailer from "nodemailer";

const transport = nodemailer.createTransport({
  host: "smtp.mailstein.com",
  port: 2525,
  secure: false,        // STARTTLS is negotiated on 2525
  auth: {
    user: "mailstein",
    pass: "ms_your_api_key",
  },
});

await transport.sendMail({
  from: "hello@yourdomain.com",
  to: "customer@example.com",
  subject: "Sent over SMTP",
  html: "<p>Same platform, your existing mailer.</p>",
});

Notes

• Use STARTTLS on port 2525 (set secure:false in Nodemailer — TLS is upgraded after connect, not implicit).
• The username is always the literal mailstein; only the password (your API key) changes per account.
• Quotas, suppression and abuse controls apply identically to SMTP and API sends.