Delivery Information API

• USPS's delivery information API performs two primary functions: tracking and confirming shipments and setting service standards to determine the length of time an order may take to ship. Programmers can allow users to track their issued order as well as select between priority mail, any special package services and express mail options on the web.
  
  

Shipping Label API

• Online retailers can use the USPS shipping label API methods to develop a variety of mailing labels. As they would be able to in a brick-and-mortar postal office, users can create shipping labels for things such as delivery confirmation, signature confirmation, express mail, merchandise return labels, customs forms and international shipping labels.
  
  

Address Information API

• The address information API offered by the USPS allows users to ensure that their package gets to its mailing destination. This API enables users to verify their address against a wide database of verified USPS mailing addresses, perform zip code look-ups, and perform official city and state information look-ups.
  
  

Rate Calculation API

• The rate calculator API enables website users to check the postage rate of the package based on its origin and destination information, as well as mailing type. It can be beneficial to add this to your ordering system so that users know what the mailing costs will be before they commit to an order. This API can calculate both international and domestic mailing rates.
  
  

Carrier Pickup API

• The carrier pickup API allows you to electronically request a mail carrier to come to your destination and pick up any packages that are available for shipment. Your packages must have shipping labels that are correctly filled out or the mail carrier will be unable to accept the package.