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Requirements & Restrictions

Outcome​

You will learn which requirements Mailhub applies to a Shipment before USPS Rates can be returned, and where the boundary sits between Mailhub's own rules and the rules USPS owns.

Mailhub publishes its own platform requirements. It does not republish USPS's service-specific policy.

Mailhub requirements​

These are Mailhub platform limits, applied to every domestic Shipment regardless of carrier — they are not USPS limits.

RequirementValue
ScopeUS domestic Shipments
Parcel weightgreater than 0
Parcel weight ceiling70 lb
Custom parcel dimensionslength, width, and height are required

A recognized predefined package can supply its own dimensions instead. Passing Mailhub validation does not guarantee that a carrier will accept the parcel.

Address and Parcel Data is the canonical reference for the full input rules — address roles, state and postal formats, character and length limits, contact requirements, and parcel validation. This page does not restate them.

USPS service coverage​

Mailhub normalizes three known USPS service names:

  • USPS Ground Advantage
  • USPS Priority Mail
  • USPS Priority Mail Express

Other USPS services may be returned with provider-supplied names. Match the known values above when you need those services, and treat an unrecognized returned serviceName as a returned service option — use its returned Rate id rather than inventing or translating a code.

See USPS with Mailhub for the recognition workflow.

Carrier-owned restrictions​

Mailhub does not republish USPS-owned eligibility or restriction policy. USPS may apply additional service-specific checks to a Shipment that satisfies every Mailhub requirement above, and a Shipment that Mailhub accepts can still be rejected further along.

Consult USPS directly for its service-specific policy. Build against the Rates actually returned for the Shipment, and see Rate Errors and Label Errors for the documented failure guidance.

Next steps​