@serve.zone/mailer

Enterprise mail server with SMTP, HTTP API, and DNS management

Overview

@serve.zone/mailer is a comprehensive mail server solution built with Deno, featuring:

• SMTP Server & Client - Full-featured SMTP implementation for sending and receiving emails
• HTTP REST API - Mailgun-compatible API for programmatic email management
• DNS Management - Automatic DNS setup via Cloudflare API
• DKIM/SPF/DMARC - Complete email authentication and security
• Daemon Service - Systemd integration for production deployments
• CLI Interface - Command-line management of all features

Architecture

Technology Stack

• Runtime: Deno (compiles to standalone binaries)
• Language: TypeScript
• Distribution: npm (via binary wrappers)
• Service: systemd daemon
• DNS: Cloudflare API integration

Project Structure

mailer/
├── bin/                    # npm binary wrappers
├── scripts/                # Build scripts
├── ts/                     # TypeScript source
│   ├── mail/              # Email implementation (ported from dcrouter)
│   │   ├── core/          # Email classes, validation, templates
│   │   ├── delivery/      # SMTP client/server, queues
│   │   ├── routing/       # Email routing, domain config
│   │   └── security/      # DKIM, SPF, DMARC
│   ├── api/               # HTTP REST API (Mailgun-compatible)
│   ├── dns/               # DNS management + Cloudflare
│   ├── daemon/            # Systemd service management
│   ├── config/            # Configuration system
│   └── cli/               # Command-line interface
├── test/                  # Test suite
├── deno.json              # Deno configuration
├── package.json           # npm metadata
└── mod.ts                 # Main entry point

Installation

Via npm (recommended)

npm install -g @serve.zone/mailer

From source

git clone https://code.foss.global/serve.zone/mailer
cd mailer
deno task compile

Usage

CLI Commands

Service Management

# Start the mailer daemon
sudo mailer service start

# Stop the daemon
sudo mailer service stop

# Restart the daemon
sudo mailer service restart

# Check status
mailer service status

# Enable systemd service
sudo mailer service enable

# Disable systemd service
sudo mailer service disable

Domain Management

# Add a domain
mailer domain add example.com

# Remove a domain
mailer domain remove example.com

# List all domains
mailer domain list

DNS Management

# Auto-configure DNS via Cloudflare
mailer dns setup example.com

# Validate DNS configuration
mailer dns validate example.com

# Show required DNS records
mailer dns show example.com

Sending Email

# Send email via CLI
mailer send \\
  --from sender@example.com \\
  --to recipient@example.com \\
  --subject "Hello" \\
  --text "World"

Configuration

# Show current configuration
mailer config show

# Set configuration value
mailer config set smtpPort 25
mailer config set apiPort 8080
mailer config set hostname mail.example.com

HTTP API

The mailer provides a Mailgun-compatible REST API:

Send Email

POST /v1/messages
Content-Type: application/json

{
  "from": "sender@example.com",
  "to": "recipient@example.com",
  "subject": "Hello",
  "text": "World",
  "html": "<p>World</p>"
}

List Domains

GET /v1/domains

Manage SMTP Credentials

GET /v1/domains/:domain/credentials
POST /v1/domains/:domain/credentials
DELETE /v1/domains/:domain/credentials/:id

Email Events

GET /v1/events

Programmatic Usage

import { Email, SmtpClient } from '@serve.zone/mailer';

// Create an email
const email = new Email({
  from: 'sender@example.com',
  to: 'recipient@example.com',
  subject: 'Hello from Mailer',
  text: 'This is a test email',
  html: '<p>This is a test email</p>',
});

// Send via SMTP
const client = new SmtpClient({
  host: 'smtp.example.com',
  port: 587,
  secure: true,
  auth: {
    user: 'username',
    pass: 'password',
  },
});

await client.sendMail(email);

Configuration

Configuration is stored in ~/.mailer/config.json:

{
  "domains": [
    {
      "domain": "example.com",
      "dnsMode": "external-dns",
      "cloudflare": {
        "apiToken": "your-cloudflare-token"
      }
    }
  ],
  "apiKeys": ["api-key-1", "api-key-2"],
  "smtpPort": 25,
  "apiPort": 8080,
  "hostname": "mail.example.com"
}

DNS Setup

The mailer requires the following DNS records for each domain:

MX Record

Type: MX
Name: @
Value: mail.example.com
Priority: 10
TTL: 3600

A Record

Type: A
Name: mail
Value: <your-server-ip>
TTL: 3600

SPF Record

Type: TXT
Name: @
Value: v=spf1 mx ip4:<your-server-ip> ~all
TTL: 3600

DKIM Record

Type: TXT
Name: default._domainkey
Value: <dkim-public-key>
TTL: 3600

DMARC Record

Type: TXT
Name: _dmarc
Value: v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com
TTL: 3600

Use mailer dns setup <domain> to automatically configure these via Cloudflare.

Development

Prerequisites

• Deno 1.40+
• Node.js 14+ (for npm distribution)

Build

# Compile for all platforms
deno task compile

# Run in development mode
deno task dev

# Run tests
deno task test

# Format code
deno task fmt

# Lint code
deno task lint

Ported Components

The mail implementation is ported from dcrouter and adapted for Deno:

• ✅ Email core (Email, EmailValidator, BounceManager, TemplateManager)
• ✅ SMTP Server (with TLS support)
• ✅ SMTP Client (with connection pooling)
• ✅ Email routing and domain management
• ✅ DKIM signing and verification
• ✅ SPF and DMARC validation
• ✅ Delivery queues and rate limiting

Roadmap

Phase 1 - Core Functionality (Current)

• Project structure and build system
• Port mail implementation from dcrouter
• CLI interface
• Configuration management
• DNS management basics
• Cloudflare DNS integration
• HTTP REST API implementation
• Systemd service integration

Phase 2 - Production Ready

• Comprehensive testing
• Documentation
• Performance optimization
• Security hardening
• Monitoring and logging

Phase 3 - Advanced Features

• Webhook support
• Email templates
• Analytics and reporting
• Multi-tenancy
• Load balancing

License

MIT © Serve Zone

Contributing

Contributions are welcome! Please see our contributing guidelines.

Support

• Documentation: https://code.foss.global/serve.zone/mailer
• Issues: https://code.foss.global/serve.zone/mailer/issues
• Email: support@serve.zone

Acknowledgments

• Mail implementation ported from dcrouter
• Inspired by Mailgun API design
• Built with Deno