ShipEngine is a multi-carrier shipping API platform that allows developers and e-commerce businesses to integrate label creation, rate shopping, address validation, and package tracking across 200+ carriers through a single API. Founded in 2016, the platform powered over one billion shipments before being rebranded as ShipStation API in late 2025 following its integration into the ShipStation brand by parent company Auctane. Existing integrations continue to work through the original ShipEngine endpoints with no required changes.
The API’s core value proposition is breadth and developer experience. Rather than maintaining separate integrations for UPS, FedEx, USPS, DHL, and dozens of regional carriers, businesses connect once and access all carrier capabilities through a unified interface. This is particularly valuable for platforms embedding shipping functionality into their product, and for 3PLs, WMSes, and ERPs that need multi-carrier support without managing carrier-specific APIs.
For direct shipment needs, ShipStation API includes pre-negotiated USPS Commercial rates and additional discounts on Ground Advantage, Priority Mail, and Priority Mail Express that are available to all plan subscribers. These discounted rates are the primary reason many small e-commerce merchants use the platform directly rather than through separate shipping software.
Pricing has two tiers. The Free plan provides access to ShipStation’s pre-negotiated carrier rates and the sandbox environment at no cost, but restricts broader API access. The Advanced plan comes in three label-volume tiers (1,000, 5,000, and 10,000 labels/month) with a subscription fee per tier, plus an additional label fee for volume that exceeds the tier. Address validation, rate shopping, tracking, and order imports each receive one free API call per label created within the monthly limit; excess calls have flat per-call overage fees. For businesses shipping more than 25,000 labels per month, enterprise pricing is available through sales.