The United States Postal Service (USPS) Web Tool Kit Application Program Interface (API) allows you to develop web-based and non web-based applications to access USPS services online. The USPS API lets you
incorporate a range of services, including Domestic Rates Calculator, Delivery Confirmation, Electronic Merchandise Return Service, and more. This technical note shows you how to communicate with USPS Web services from 4D using 4D Internet commands.

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