Skymail

A robust TypeScript email service package with automatic failover and multiple provider support. Built for reliability and ease of use in modern Node.js applications.

Features

• Automatic Failover: Seamlessly switch between providers to ensure delivery
• Multiple Provider Support:
  • SendGrid
  • Mailgun
  • Extensible architecture for custom providers
• TypeScript First: Full type safety and comprehensive definitions
• Reliability Features:
  • Priority-based provider selection
  • Automatic retry mechanism
  • Health monitoring
  • Configurable timeouts
• Developer Experience:
  • Clean, intuitive API
  • Comprehensive error handling
  • Detailed logging options

Installation

npm install skymail

Quick Start

import { EmailService, SendGridProvider, MailgunProvider } from 'skymail';

// Initialize providers
const sendgrid = new SendGridProvider({
  apiKey: 'YOUR_SENDGRID_API_KEY',
  maxRetries: 3,
  retryDelay: 1000
});

const mailgun = new MailgunProvider({
  apiKey: 'YOUR_MAILGUN_API_KEY',
  domain: 'YOUR_DOMAIN',
  maxRetries: 3,
  retryDelay: 1000
});

// Create service with failover
const emailService = new EmailService([
  { provider: sendgrid, priority: 1 },  // Primary
  { provider: mailgun, priority: 2 }    // Backup
]);

// Send email
try {
  const success = await emailService.sendEmail({
    to: 'recipient@example.com',
    from: 'sender@yourdomain.com',
    subject: 'Hello!',
    text: 'Message content',
    html: '<p>Message content</p>'
  });

  console.log('Email sent:', success);
} catch (error) {
  console.error('Failed to send:', error);
}

Architecture

The package follows a modular design with three main components:

1. Email Service: Orchestrates sending process and manages providers
2. Providers: Implement email sending logic for specific services
3. Core Abstractions: Define interfaces and base classes

Provider Configuration

SendGrid

interface SendGridConfig {
  apiKey: string;          // Required
  maxRetries?: number;     // Optional (default: 3)
  retryDelay?: number;     // Optional (default: 1000ms)
}

Mailgun

interface MailgunConfig {
  apiKey: string;         // Required
  domain: string;         // Required
  maxRetries?: number;    // Optional (default: 3)
  retryDelay?: number;    // Optional (default: 1000ms)
}

Email Message Options

interface EmailMessage {
  to: string | string[];
  from: string;
  subject: string;
  text: string;
  html?: string;
  cc?: string | string[];
  bcc?: string | string[];
  replyTo?: string;
  attachments?: Array<{
    filename: string;
    content: Buffer | string;
    contentType?: string;
  }>;
}

Advanced Usage

Custom Provider

import { AbstractEmailProvider, EmailMessage } from 'skymail';

export class CustomProvider extends AbstractEmailProvider {
  constructor(config: YourConfig) {
    super(config);
  }

  protected async sendEmailRequest(message: EmailMessage): Promise<boolean> {
    // Implement provider-specific sending logic
    return true;
  }

  public async isAvailable(): Promise<boolean> {
    // Implement availability check
    return true;
  }
}

Provider Management

// Add new provider
emailService.addProvider(newProvider, 3);

// Remove provider
emailService.removeProvider(existingProvider);

// Update priority
emailService.updatePriority(existingProvider, 2);

// Check status
const status = await emailService.getProvidersStatus();

Error Handling

try {
  const result = await emailService.sendEmail(message);
  if (!result) {
    // All providers failed
  }
} catch (error) {
  if (error instanceof InvalidEmailError) {
    // Handle validation errors
  } else {
    // Handle other errors
  }
}

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

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

Support

• Issues: GitHub Issues
• Documentation: Full Documentation