Complete implementation of newsletter sending system with SendGrid integration:
Backend Implementation:
- EmailService class with template rendering (Handlebars)
- sendNewsletter() method with subscriber iteration
- Preview and send controller methods
- Admin routes with CSRF protection and authentication
- findByInterest() method in NewsletterSubscription model
Frontend Implementation:
- Newsletter send form with validation
- Preview functionality (opens in new window)
- Test send to single email
- Production send to all tier subscribers
- Real-time status updates
Dependencies:
- handlebars (template engine)
- @sendgrid/mail (email delivery)
- html-to-text (plain text generation)
Security:
- Admin-only routes with authentication
- CSRF protection on all POST endpoints
- Input validation and sanitization
- Confirmation dialogs for production sends
Next steps: Configure SendGrid API key in environment variables
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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