Zipwise Free ZIP code web services

This tool allows to developers to submit standard web API requests and receive XML or JSON responses back. Look up current ZIP code data or city data, perform radius searches, and find the distance between two locations. Includes US and Canada ZIP codes.

Available services:

zipinfo: Returns full information about a requested ZIP code.

citysearch: Returns all ZIP codes matching a text search by city name or substring.

distance: Returns the Great Circle distance between two ZIP codes.

radius: Returns all ZIP codes within a requested radius of a requested ZIP code.


More information: http://www.zipwise.com/webservices/