Secure SMTP Email Service

A professional, secure email-sending service built with Next.js, TypeScript, and Nodemailer. Features encrypted SMTP connections, multiple provider support, and beautiful HTML email templates.

🚀 Features

• Secure SMTP Configuration: TLS/SSL encryption enforced
• Multiple SMTP Providers: Gmail, SendGrid, Mailgun, AWS SES, Outlook
• Professional Email Templates: HTML templates with inline CSS
• Environment Variable Security: No hardcoded credentials
• Input Validation & Sanitization: Prevents injection attacks
• Error Handling: Comprehensive error handling and logging
• Real-time Testing: Send test emails to real addresses
• Health Check Endpoint: Monitor SMTP service status

📋 Prerequisites

• Node.js 18+ and npm/yarn
• SMTP provider account (Gmail, SendGrid, etc.)
• Environment variables configured

🛠️ Installation

1. Clone and install dependencies: ```bash npm install ```

2. Configure environment variables: ```bash cp .env.example .env.local ```

3. Edit .env.local with your SMTP credentials: ```env SMTP_HOST=smtp.gmail.com SMTP_PORT=587 SMTP_USER=your-email@gmail.com SMTP_PASS=your-app-password FROM_EMAIL=your-email@gmail.com FROM_NAME=Your App Name ```

4. Start the development server: ```bash npm run dev ```

🔧 SMTP Provider Setup

Gmail Setup

1. Enable 2-Factor Authentication
2. Generate App Password: Google Account → Security → App passwords
3. Use the 16-character app password in SMTP_PASS

SendGrid Setup

1. Create SendGrid account
2. Generate API key
3. Use apikey as SMTP_USER and API key as SMTP_PASS

Mailgun Setup

1. Create Mailgun account
2. Add and verify your domain
3. Use SMTP credentials from Mailgun dashboard

AWS SES Setup

1. Set up AWS SES and verify domain/email
2. Create SMTP credentials in SES console
3. Use provided SMTP username and password

📧 Email Templates

The service includes three professional email templates:

1. Welcome Email: User onboarding with call-to-action
2. Notification Email: System alerts and updates
3. Custom Email: Flexible template for custom messages

All templates feature:

• Responsive design
• Inline CSS for email client compatibility
• Dynamic content placeholders
• Professional styling
• Plain text fallbacks

🔒 Security Features

• TLS/SSL Encryption: All SMTP connections encrypted
• Environment Variables: Sensitive data stored securely
• Input Validation: Email addresses and content validated
• Sanitization: User inputs sanitized to prevent injection
• Connection Timeouts: Prevents hanging connections
• Error Handling: Secure error messages without exposing internals

🧪 Testing

Send Test Email

1. Open the application in your browser
2. Fill out the test form with recipient details
3. Choose an email template
4. Click "Send Email"

Health Check

Visit /api/send-email (GET request) to check SMTP service status.

API Usage

```javascript const response = await fetch('/api/send-email', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ to: 'recipient@example.com', subject: 'Test Email', name: 'John Doe', template: 'welcome' }) }) ```

📊 Error Handling

The service handles various error scenarios:

• SMTP authentication failures
• Connection timeouts
• Invalid email addresses
• Server downtime
• Rate limiting

🚀 Deployment

Vercel Deployment

1. Push code to GitHub
2. Connect repository to Vercel
3. Add environment variables in Vercel dashboard
4. Deploy

Environment Variables for Production

Ensure all SMTP environment variables are set in your production environment.

📈 Monitoring

• Health check endpoint: GET /api/send-email
• Console logging for sent emails
• Error tracking and reporting

🔧 Customization

Adding New Templates

1. Add template case in lib/email-templates.ts
2. Create HTML and text versions
3. Update TypeScript types

Custom SMTP Providers

Add new provider configurations in the .env.example file and update documentation.

📝 Best Practices

1. Use App Passwords: For Gmail and other providers requiring 2FA
2. Verify Domains: Set up SPF, DKIM, and DMARC records
3. Monitor Reputation: Keep track of bounce rates and spam reports
4. Rate Limiting: Implement rate limiting for production use
5. Logging: Monitor email sending for debugging and analytics

🐛 Troubleshooting

Common Issues

Authentication Failed

• Verify SMTP credentials
• Check if 2FA is enabled (Gmail requires App Password)
• Ensure correct SMTP host and port

Connection Timeout

• Check firewall settings
• Verify SMTP host is accessible
• Try different ports (587, 465, 25)

Emails Not Delivered

• Check spam folder
• Verify sender reputation
• Set up proper DNS records (SPF, DKIM, DMARC)

📄 License

MIT License - feel free to use this in your projects!