A ZIP Code is a postal code that the U.S. Postal service relies on to help sort and deliver mail. ZIP is short for Zone Improvement Plan, and was implemented by the U.S. Postal Service in 1963, to help "zip" along mail delivery.
Developers who are producing shipping, eCommerce, or location-based services may find that determining ZIP codes and/or International postal codes is a crucial feature for a successful application. In order to accomplish this, developers would need a suitable ZIP Codes API.