A ZIP Code is a postal code used by the United States Postal Service (USPS) in a system it introduced in 1963. The term ZIP is an acronym for Zone Improvement Plan; it was chosen to suggest that the mail travels more efficiently and quickly (zipping along) when senders use the code in the postal address. The basic format consists of five digits. (wikipedia)
ZIP code generator produces random, 5-digit ZIP codes.
This tool was developed for programmers and testers who have the constant need to enter different ZIP codes in developing forms.