Documentation

JustSMTP is a drop-in SMTP relay in front of Amazon SES. Point your existing mailer at smtp.justsmtp.com, authenticate with a credential pair generated in the dashboard, and send. No AWS account, no IAM policies.

Connection settings

These don't change — safe to hard-code or drop straight into an env file.

host	smtp.justsmtp.com
port (STARTTLS)	587
port (dev / restrictive networks)	2525 — STARTTLS, same credentials
auth mechanisms	AUTH LOGIN, AUTH PLAIN
username / password	Generated per credential pair from the dashboard. Shown once at creation — store it in your secrets manager or .env, not source control.

How it works

01 Your application connects to smtp.justsmtp.com over STARTTLS and authenticates with the username and password from a credential pair.
02 We accept the message over SMTP, check the sending domain's DKIM and SPF, and hand it off to Amazon SES for delivery.
03 Every attempt — sent, deferred, bounced, dropped — lands in your activity log with the real upstream SMTP response. We don't retain message bodies; the log keeps metadata and the subject line only.

Integrations

JustSMTP works with any SMTP client. Swap the host, port, and credentials into your existing mailer — nothing else changes.

Node.js

nodemailer

// npm install nodemailer
import nodemailer from 'nodemailer';
 
const transport = nodemailer.createTransport({
  host: 'smtp.justsmtp.com',
  port: 587,
  secure: false,
  auth: {
    user: process.env.SMTP_USER,
    pass: process.env.SMTP_PASS,
  },
});
 
await transport.sendMail({
  from: '"Acme" <hello@mail.acme.io>',
  to: 'sarah@figma.com',
  subject: 'Welcome to Acme',
  html: '<b>You are in.</b>',
});

Python

smtplib

# stdlib — no install required
import os, smtplib
from email.message import EmailMessage
 
msg = EmailMessage()
msg["From"] = "Acme <hello@mail.acme.io>"
msg["To"] = "sarah@figma.com"
msg["Subject"] = "Welcome to Acme"
msg.set_content("You are in.")
 
with smtplib.SMTP("smtp.justsmtp.com", 587) as server:
    server.starttls()
    server.login(os.environ["SMTP_USER"], os.environ["SMTP_PASS"])
    server.send_message(msg)

Ruby

mail

# gem install mail
require 'mail'
 
Mail.defaults do
  delivery_method :smtp, {
    address:              'smtp.justsmtp.com',
    port:                 587,
    user_name:            ENV['SMTP_USER'],
    password:             ENV['SMTP_PASS'],
    authentication:       :plain,
    enable_starttls_auto: true,
  }
end
 
Mail.deliver do
  from    'hello@mail.acme.io'
  to      'sarah@figma.com'
  subject 'Welcome to Acme'
  body    'You are in.'
end

PHP

Swift_Mailer

<?php
$transport = (new Swift_SmtpTransport('smtp.justsmtp.com', 587, 'tls'))
    ->setUsername(getenv('SMTP_USER'))
    ->setPassword(getenv('SMTP_PASS'));
 
$mailer = new Swift_Mailer($transport);
 
$message = (new Swift_Message('Welcome to Acme'))
    ->setFrom(['hello@mail.acme.io' => 'Acme'])
    ->setTo(['sarah@figma.com'])
    ->setBody('You are in.');
 
$mailer->send($message);