SwiftMail Backend

⚡ Fast, reliable, and scalable email delivery platform built with Go.

🚀 Features

• High-Performance Email Delivery - Send thousands of emails per second
• Real-Time Analytics - Track opens, clicks, deliveries, and bounces
• Multi-Provider Support - SMTP, SendGrid, AWS SES, and more
• Advanced Queue Management - Redis-based job queue with priority handling
• Domain Management - SPF, DKIM, and DMARC configuration
• Template Engine - Dynamic email templates with variable substitution
• Suppression Lists - Automatic bounce and complaint handling
• Webhook Support - Real-time event notifications
• API Key Management - Secure authentication with rate limiting
• Credit System - Top-up based billing model

📋 Prerequisites

• Go 1.21 or higher
• PostgreSQL 14+
• Redis 7+
• SendGrid account (or other SMTP provider)

🛠️ Installation

1. Clone the repository

git clone https://github.com/Mark-0731/SwiftMail-BE.git
cd SwiftMail-BE

2. Install dependencies

go mod download

3. Configure environment variables

cp .env.example .env
# Edit .env with your configuration

4. Run database migrations

go run cmd/migrate/main.go

5. Start the API server

go run cmd/api/main.go

6. Start the worker (in another terminal)

go run cmd/worker/main.go

🔧 Configuration

Key environment variables:

# Server
SERVER_PORT=8080
APP_ENV=production

# Database
DB_HOST=localhost
DB_PORT=5432
DB_USER=postgres
DB_PASSWORD=your_password
DB_NAME=swiftmail

# Redis
REDIS_HOST=localhost
REDIS_PORT=6379

# SMTP
SMTP_HOST=smtp.sendgrid.net
SMTP_PORT=587
SMTP_USERNAME=apikey
SMTP_PASSWORD=your_sendgrid_api_key

# JWT
JWT_ACCESS_SECRET=your_secret_key
JWT_REFRESH_SECRET=your_refresh_secret

📚 API Documentation

Authentication

All API requests require an API key in the header:

X-API-Key: sm_live_your_api_key

Send Email

POST /v1/mail/send
Content-Type: application/json

{
  "from": "sender@example.com",
  "to": "recipient@example.com",
  "subject": "Hello World",
  "html": "<h1>Hello!</h1>",
  "text": "Hello!"
}

Get Email Logs

GET /v1/mail/logs?page=1&limit=50

Track Analytics

GET /v1/analytics/summary?start_date=2024-01-01&end_date=2024-01-31

🏗️ Architecture

SwiftMail-BE/
├── cmd/
│   ├── api/          # API server entry point
│   ├── worker/       # Background worker entry point
│   ├── migrate/      # Database migrations
│   └── smtp/         # SMTP server (optional)
├── internal/
│   ├── config/       # Configuration management
│   ├── features/     # Feature modules (DDD structure)
│   │   ├── auth/     # Authentication & authorization
│   │   ├── email/    # Email sending logic
│   │   ├── analytics/# Analytics tracking
│   │   ├── billing/  # Credit system
│   │   └── ...
│   ├── platform/     # Infrastructure layer
│   │   ├── queue/    # Job queue (Asynq)
│   │   ├── cache/    # Redis cache
│   │   └── provider/ # Email providers
│   └── server/       # HTTP server setup
├── pkg/              # Shared packages
│   ├── database/     # Database utilities
│   ├── metrics/      # Prometheus metrics
│   └── tracking/     # Email tracking
└── migrations/       # SQL migrations

🧪 Testing

Run tests:

go test ./...

Run tests with coverage:

go test -cover ./...

📊 Monitoring

SwiftMail exposes Prometheus metrics at:

• API: http://localhost:9091/metrics
• Worker: http://localhost:9092/metrics

Key metrics:

• swiftmail_emails_sent_total - Total emails sent
• swiftmail_emails_failed_total - Total failed emails
• swiftmail_email_send_duration_seconds - Email send latency

🔒 Security

• API keys are hashed using bcrypt
• JWT tokens for session management
• Rate limiting on all endpoints
• SQL injection prevention with parameterized queries
• CORS protection
• Request ID tracking for audit logs

🤝 Contributing

See CONTRIBUTING.md for contribution guidelines.

📄 License

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

🐛 Bug Reports

Please report bugs via GitHub Issues.

📧 Support

For support, email support@swiftmail.com or join our Discord community.

🙏 Acknowledgments

• Fiber - Web framework
• Asynq - Job queue
• GORM - ORM library
• SendGrid - Email delivery

---

Made with ❤️ by the SwiftMail Team