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Carrier Availability

What carrier availability means​

Rate and Label outcomes can depend on the current Account or authorized optional Sub-account context, the current configured environment, account readiness, Shipment origin/destination/Parcel data, and the requested operation.

Documented scope is not the same as available scope​

The operations are carrier-agnostic. Rate results carry whatever carrier and serviceName values your Account, optional Sub-account, and environment configuration produce for the Shipment you are rating, and every one of them is used through the same Rates and Label operations, with no carrier-specific request path.

Only some carriers have a dedicated guide on this portal, and that reflects what has been documented rather than what the platform can rate or label. Read it in neither direction as a capability statement: the absence of a guide is not an absence of support, and the presence of one is not a promise of availability to your Account.

Sample JSON throughout the documentation names carriers only to illustrate the response shape. Those names are not a supported-carrier list. Treat a returned Rate as the only evidence that a carrier and service can be used for a given Shipment.

Private setup boundary​

Complete any required carrier setup in the authenticated Mailhub application. Carrier configuration and management are not exposed through public integration endpoints.

Readiness checks​

Before relying on a Rate or beginning state-changing work, check:

  • valid API credentials and the intended Account or optional Sub-account;
  • completed account setup where applicable;
  • valid Address and Parcel data for the Shipment;
  • wallet or funding readiness where applicable to state-changing work;
  • the returned public results and errors for the requested operation.

Wallet or funding readiness is not documented here as a condition for returning a Rate.

No-guarantee boundaries​

A configured or visible carrier does not guarantee that every Shipment returns a Rate. Passing Mailhub request validation does not guarantee carrier acceptance.

Public documentation does not promise a specific carrier, service, price, transit time, billing model, or availability.

When a Rate is unavailable​

Inspect the actual public response and error envelope. Validate Shipment input, confirm the intended Account or optional Sub-account context, and review applicable account readiness before making another request. Avoid a blind retry with unchanged invalid input.