Postmen API
Postmen (now AfterShip Shipping) is an API-first product: REST endpoints for rates, labels, manifests, pickups, and address validation with SDKs in six languages. API keys are self-serve and the API itself is free; volume and dashboard features sit on paid plans.
Frequently asked questions
Postmen scores A on Supergood's API Report Card. Postmen (now AfterShip Shipping) is an API-first product: REST endpoints for rates, labels, manifests, pickups, and address validation with SDKs in six languages. API keys are self-serve and the API itself is free; volume and dashboard features sit on paid plans.
Postmen has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
Postmen is a multi-carrier shipping API from AfterShip, the same Hong Kong-headquartered company behind the AfterShip post-purchase tracking platform, that gives developers a single REST interface for calculating live shipping rates, generating labels and customs documents, scheduling pickups, transmitting end-of-day manifests, and validating addresses across 100+ couriers.
Primary vertical: Fleet / Trucking / Logistics, specifically the multi-carrier shipping abstraction layer used by ecommerce platforms, marketplaces, 3PLs, ERP/OMS vendors, and direct-to-consumer brands that need to print labels and rate-shop across UPS, FedEx, USPS, DHL, TNT, Canada Post, Australia Post, Royal Mail, DPD, GLS, China Post, SF Express, and regional carriers without negotiating individual API contracts with each one. A Shopify-based DTC brand or a custom storefront calls POST /rates with origin, destination, package weight, and dimensions to retrieve live rates from every connected carrier account, picks the cheapest qualifying service, then calls POST /labels to generate a PDF/PNG/ZPL label and tracking number in a single request.
Moderate-to-high within the developer-shipping niche.
Postmen sits directly in the fulfillment critical path: every label generated represents a customer order that must ship today, and every failed /rates call shows up as missing shipping options at checkout that drive cart abandonment.
Postmen launched around 2014–2015 as AfterShip's developer-facing shipping API, predating the broader ShipEngine and Shippo product launches in the same space.
Supergood's grades measure one thing: can a customer's engineering team get their own data out programmatically? Supergood checks six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and rolls them into a letter grade. Supergood re-verifies grades, and they only move on evidence.
Postmen has partial MCP support. Parent company AfterShip publishes an official MCP server for its Tracking and Returns APIs with activity in 2026, but it does not cover the Postmen shipping label API and its documentation is minimal.
Partially. MCP support for Postmen exists but is incomplete, so what MCP clients like Claude, Cursor, and Codex can reach depends on what the available server covers.