EasyPost API
Multi-carrier shipping API that normalizes label creation, rate shopping, address verification, and tracking across 100+ carriers (UPS, USPS, FedEx, DHL, etc.) through a single unified interface.
AfterShip API
Unified shipment tracking API aggregating tracking data from 900+ carriers worldwide. Provides real-time tracking status, webhooks for tracking events, and customer notification infrastructure.
Shippo API
Multi-carrier shipping API for creating discounted labels, comparing rates, tracking packages, and managing returns across major carriers (USPS, UPS, FedEx, DHL, etc.).
ShipStation API
Multi-channel order management and shipping platform API. Centralizes orders from Amazon, eBay, Shopify, and 100+ stores, then manages fulfillment, label creation, and tracking across all channels.