Mailhub API Release Notes

August 11, 2026Documentation

Published label contract corrected to match what the API returns

The published OpenAPI contract described label values the API does not produce. Format 3 was documented as an Epl2 format and format 4 was missing; the label response was documented with labelZplUrl and labelEpl2Url fields. The service itself never changed: it accepts 1 Pdf, 2 Zpl300Dpi, 3 Zpl203Dpi and 4 Zpl600Dpi, returns PDF or ZPL bytes only, and returns one label URL per ZPL resolution — labelZpl203Url, labelZpl300Url and labelZpl600Url. The contract, the API Reference, the Postman collection, and the guides now document those values. If your integration was written against the old documented field names, it was reading fields the API never sent; switch to the resolution-specific fields.

View the affected operation in the API Reference.

View the affected operation in the API Reference.

August 6, 2026Beta

Mailhub released to production for beta testing

Mailhub was released to the production environment for beta testing. The public API described in this portal — Auth, Orders, Shipments, and Labels — is available to beta participants against production credentials. Request and response formats are the ones the API Reference and the Postman collection document. Beta behavior can still change, so review the request, response, and error behavior of an operation before you depend on it.