eternalscloud/mailer

What is Eternals Cloud Mailer?

Eternals Cloud Mailer is an email testing tool for developers. It captures emails sent by your application during development so you can inspect them in a clean web UI. Point your app's SMTP config at Eternals Cloud Mailer, and every outgoing email lands in your local inbox — safely, instantly.

Features

• Token-based Authentication — Secure API access with JWT tokens
• Real-time Email Capture — Instant capture of all outgoing emails via SMTP
• Full Message Inspection — View HTML/text bodies, headers, and attachments
• Environment-based Configuration — Simple setup via environment variables
• Modern Web UI — Clean React interface with dark mode support

Use Cases

• Test email templates — Preview and validate email layouts before production
• Debug email delivery — Inspect headers, content, and attachments during development
• Verify SMTP integration — Confirm your app's email functionality without sending real emails
• QA workflows — Review automated emails in a safe, isolated environment

How to Use This Image

Quick Start

bash
docker run -d \
  --name ec-mailer \
  --restart always \
  -p 8502:8502 \
  -p 1025:1025 \
  -e POSTGRES_URL=postgresql://username:password@hostname:5432/mailer \
  -v mailer:/app/attachments \
  eternalscloud/mailer:latest

Once the container is running:

• Web UI: Open http://localhost:8502 in your browser
• SMTP Server: Configure your application to send mail to localhost:1025

Connecting Your Application

Configure your application's SMTP settings to point to Eternals Cloud Mailer:

Node.js (Nodemailer)

javascript
const transporter = nodemailer.createTransport({
  host: 'localhost',
  port: 1025,
  secure: false
});

Python (smtplib)

python
import smtplib

with smtplib.SMTP('localhost', 1025) as server:
    server.sendmail(sender, recipient, message)

Go (net/smtp)

go
err := smtp.SendMail(
    "localhost:1025",
    nil,
    sender,
    []string{recipient},
    []byte(message),
)

Environment Variables

POSTGRES_URL format:

• username / password — PostgreSQL credentials
• hostname — database host or Docker service name (e.g. db in Compose, localhost on the host)
• 5432 — default PostgreSQL port
• mailer — database name

Exposed Ports

Volumes

Important: Mount a volume to /app/attachments to persist email attachments across container restarts.

Docker Compose

A complete example with PostgreSQL database:

yaml
services:
  ec-mailer:
    image: eternalscloud/mailer:latest
    container_name: ec-mailer
    restart: always
    ports:
      - "8502:8502"
      - "1025:1025"
    environment:
      - POSTGRES_URL=postgresql://username:password@hostname:5432/mailer
    volumes:
      - mailer:/app/attachments
    depends_on:
      - db

  db:
    image: postgres:18.4
    restart: always
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mailer
    volumes:
      - postgres:/var/lib/postgresql/data

volumes:
  mailer:
  postgres:

In this stack, set hostname to db (the Postgres service name below). Use credentials that match POSTGRES_USER / POSTGRES_PASSWORD on the db service.

Run with:

bash
docker compose up -d

Where to Get Help

• Documentation: View full documentation
• Report Issues: Submit bugs or feature requests

License

This project is licensed under the MIT License — see the LICENSE file for details.