How to Build Multi-Carrier Shipping (Rates, Labels, Tracking) using a Unified Shipping API

Unified's Shipping API enables businesses to streamline multi-carrier shipping processes by allowing them to manage shipments, retrieve rates, generate labels, and track deliveries through a single API, reducing the need for multiple integrations with carriers like Shippo, EasyPost, FedEx, UPS, DHL, and USPS. The workflow involves creating a shipment object that acts as a central point for addresses, packages, and fulfillment details, retrieving and selecting rates based on criteria such as cost or delivery speed, and generating shipping labels that include tracking information. Tracking delivery status is managed through an event-driven approach, using webhooks where available and incremental polling otherwise, to ensure consistent updates across all carrier integrations. The API supports extended scenarios like international shipping, returns, and delivery controls, and emphasizes the importance of maintaining shipment state and synchronization through pagination and timestamp-based updates. This setup offers a simplified, unified solution for managing multi-carrier shipping logistics efficiently.