This is a submission for the Postmark Challenge: Inbox Innovators.

What I Built

I built Travel Itinerary Builder – an AI-powered service that transforms scattered travel booking confirmations into organized, comprehensive trip plans through simple email forwarding. No apps, no accounts, just email.

The Problem: Travelers receive confirmation emails from various sources (airlines, hotels, car rentals, restaurants) creating a mess of scattered information that’s time-consuming to organize manually.

The Solution: Forward booking confirmations to a unique trip email address and receive back beautiful, AI-enhanced itineraries with:

• 📧 Email-First Interface: Everything works through email forwarding
• 🤖 AI-Powered Parsing: Automatically extracts details from any booking format
• 🗓️ Smart Organization: Chronological timeline with all trip events
• 🌟 AI Recommendations: Local restaurants, attractions, and daily plans with clickable Google Maps links
• 📱 Mobile-Friendly: Beautiful HTML emails that work on any device
• 🔗 Structured Output: Guaranteed valid responses using OpenAI function calling

Key Features:

• Create trips with “NEW TRIP” email subject
• Forward any booking confirmation to your unique trip address
• Get comprehensive itineraries with “GET ITINERARY” request
• AI generates restaurant recommendations, sightseeing suggestions, daily plans, navigation, local tips, weather info, and cultural etiquette
• All responses include clickable links and practical information

Demo

🔗 Demo: Youtube Video

Important Note for Testing: Currently, due to Postmark’s pending approval restrictions, I’m limited to sending emails only within my domain. External email testing is temporarily unavailable. Please check the video demonstration and GitHub repository for a complete overview of the functionality. The system works perfectly as shown in the demo.

Screenshots:

Welcome Email

Clean welcome email with unique trip address and instructions

Booking Confirmation

Instant confirmation when bookings are added to your trip

AI-Enhanced Itinerary

Beautiful HTML itinerary with timeline, AI recommendations, and clickable links

Mobile-Responsive Design

Perfectly formatted for mobile email clients

Code Repository

🔗 GitHub Repository: https://github.com/turazashvili/travelAI

The repository includes:

• Complete NestJS TypeScript backend
• AI parsing with OpenAI function calling
• Postmark integration for inbound/outbound emails
• MongoDB data models for flexible trip storage
• Beautiful HTML email templates
• Comprehensive demo script and documentation

How I Built It

Tech Stack

• Backend: NestJS with TypeScript
• Database: MongoDB for flexible trip and event storage
• Email Service: Postmark for both inbound and outbound email processing
• AI Processing: OpenAI GPT-4o-mini with function calling for structured responses
• Deployment: Sevalla with automatic deployments
• Package Manager: pnpm for fast dependency management

Implementation Process

1. Email-First Architecture

I designed the system around email as the primary interface because:

• No app downloads or account creation needed
• Works on any device with email
• Familiar interface for all users
• Perfect for travel when you need quick access

2. Postmark Integration

Postmark was crucial for both directions:

Inbound Processing:

// Webhook endpoint for processing forwarded emails
@Post('inbound')
async handleInboundEmail(@Body() emailData: PostmarkInboundEmail) {
  // Route emails based on subject and destination
  if (subject.toUpperCase().includes('NEW TRIP')) {
    await this.handleNewTripRequest(fromEmail);
  } else if (subject.toUpperCase().includes('GET ITINERARY')) {
    await this.handleItineraryRequest(fromEmail, toEmail);
  } else {
    await this.handleBookingEmail(fromEmail, toEmail, subject, textBody);
  }
}

Outbound Email Generation:

await this.postmarkClient.sendEmail({
  From: process.env.FROM_EMAIL,
  To: userEmail,
  Subject: '🗓️ Your AI-Enhanced Travel Itinerary',
  HtmlBody: htmlContent,
  TextBody: textContent,
});

3. AI-Powered Enhancement

The real innovation came with AI integration:

Smart Parsing: Any booking confirmation format gets parsed using OpenAI
Structured Output: Using function calling to guarantee valid JSON responses
Rich Recommendations: AI generates comprehensive travel suggestions with real links

// OpenAI Function Calling for guaranteed JSON structure
const completion = await this.openai.chat.completions.create({
  model: 'gpt-4o-mini',
  messages: [...],
  functions: [{
    name: "generate_suggestions",
    description: "Generate comprehensive travel destination recommendations",
    parameters: {
      type: "object",
      properties: {
        restaurants: { /* detailed schema */ },
        sightseeing: { /* detailed schema */ },
        activities: { /* detailed schema */ },
        // ... more structured properties
      }
    }
  }],
  function_call: { name: "generate_suggestions" }
});

4. MongoDB Flexibility

Used MongoDB for its flexible schema to handle any booking type:

interface TravelEvent {
  type: string; // 'flight' | 'hotel' | 'car' | 'restaurant' | 'activity' | any custom type
  title: string;
  startDateTime?: Date;
  location?: LocationData;
  parsedData: Record<string, any>; // flexible for any extracted data
  confidence: number; // AI parsing confidence
}

5. Beautiful Email Templates

Created responsive HTML email templates that work across all email clients:

• Horizontal stats layout for trip overview
• Clean timeline with emojis and formatting
• Clickable Google Maps links for all suggestions
• Mobile-responsive design
• Fallback text versions

Experience with Postmark

Postmark exceeded expectations in several ways:

Reliability: 100% email delivery during development and testing
Speed: Sub-second processing for both inbound and outbound emails

Developer Experience: Clean API, excellent documentation, helpful error messages
Webhook Processing: Rock-solid inbound email parsing with rich metadata
Template Support: Great HTML email rendering across email clients

Challenges Overcome:

• Initially tried custom email headers for threading, learned to work within Postmark’s constraints
• Optimized email parsing for various booking confirmation formats
• Handled rate limiting gracefully for AI processing

Key Postmark Features Used:

• Inbound email processing with webhooks
• Outbound email API with HTML/text content
• Message streams for better organization
• Delivery tracking and error handling

Why This Project Stands Out

1. Zero Friction UX: No downloads, signups, or new interfaces to learn
2. AI Enhancement: Goes beyond organization to provide valuable travel insights
3. Universal Compatibility: Works with any email client, any booking provider
4. Practical Value: Solves a real problem every traveler faces
5. Scalable Architecture: Built to handle various booking formats and destinations

Future Enhancements

• Real-time flight status updates
• Weather integration for packing suggestions
• Collaborative trip planning for groups
• Calendar integration (iCal export)
• Expense tracking and budget insights

This project showcases how email can be reimagined as a powerful interface for AI-powered services, with Postmark providing the reliable infrastructure to make it all possible.

Built with ❤️ using Postmark’s excellent email infrastructure