Dispatch Shipping System

Context

The organization needed to ship equipment to employees across three continents — laptops for onboarding, return boxes for offboarding, replacement hardware for swaps. Each shipment required manual carrier selection, label generation, and printing. There was no unified system connecting orders to labels to physical printers.

Challenge

The solution had to support multiple shipping scenarios (one-way outbound, round-trip with return labels, digital return labels), integrate with multiple carriers through EasyPost, automatically handle insurance for high-value shipments, and connect to physical Zebra printers on the local network. All orchestrated from a simple warehouse-facing UI.

Solution

A three-component system — API, frontend, and containerized deployment:

FastAPI Backend (buy-shipping-label): Orchestrates the complete shipping lifecycle. Services include OutboundShippingService, RoundTripShippingService, LabelPrinterService, and OrderManager. Integrates with EasyPost for multi-carrier rate shopping and label generation, Airtable for order data, and networked Zebra printers.

Flutter Frontend (dispatch): Warehouse-facing app for order lookup, rate comparison, label purchase, and one-click printing. Displays real-time status updates throughout the workflow.

Docker Deployment (dispatch_docker): Containerized backend with GitHub Container Registry distribution, configurable environment variables, and automatic restart capability.

┌─────────────┐     ┌──────────────┐     ┌──────────────┐
│  Flutter UI │────▶│   FastAPI    │────▶│   EasyPost   │
│  (Warehouse)│     │  (Backend)   │     │  (Carriers)  │
└─────────────┘     └──────┬───────┘     └──────────────┘
                           │
              ┌────────────┼────────────┐
              ▼            ▼            ▼
       ┌──────────┐ ┌──────────┐ ┌──────────┐
       │ Airtable │ │  Zebra   │ │  Docker  │
       │ (Orders) │ │ (Print)  │ │ (Deploy) │
       └──────────┘ └──────────┘ └──────────┘

Deployment

Deployed on the local network via Docker with environment-specific configuration for test and production EasyPost modes. The system connects to Airtable for order data, EasyPost for carrier operations, and the ZPL-Docker print service for physical label output. Frontend deployed for warehouse staff with direct API access.

Impact

• Automated multi-carrier rate shopping and label generation
• Supported equipment logistics for 250+ employees across 3 continents
• One-click label purchase and printing from warehouse UI
• Automatic insurance for shipments over $100 value