Custom Shopify App for ATS Healthcare Integration

I'm looking for an experienced Shopify App developer who can create a custom app to connect my Shopify store with ATS Healthcare's shipping API.

Key Functionalities:
- Order Synchronization: The app should seamlessly sync orders from Shopify to the ATS Healthcare shipping platform.
- Shipping Rate Calculation: The app should calculate shipping rates in real-time, providing customers with accurate shipping costs at checkout.
- Tracking Updates: Customers should be able to receive tracking updates directly from the app.

Custom Features:
- Automated Return Management: The app should facilitate easy return processes, automating as much of the process as possible.
- Customer Notifications: The app should notify customers of their order status via email or SMS, providing a transparent and proactive customer service experience.
- Inventory Management Integration: The app should integrate with my existing inventory management system, providing real-time inventory updates and preventing stock-related issues.

Ideal Skills:
- Shopify App Development
- API Integration
- Inventory Management Systems
- Customer Notification Systems
- Return Management Systems

Experience with ATS Healthcare's shipping API is a plus. Please provide examples of similar projects you have completed in your bid.