Free API for Parsing US Postal Addresses?

Question

I'd like to use an API to parse US Postal addresses input into an ASP.NET application. I will store the input address, no matter how it's input, then attempt to parse and verify with the user.

Does Google, Microsoft or Yahoo have such functionality in their APIs? If so, what is your experience with the various APIs?

Answer 1

USPS provides its own API as long as everything is inside the US:

USPS - Address Information APIs

Answer 2

I don't know how reliable these are but

http://www.webservicex.net/uszip.asmx

http://codebump.com/services/zipcodelookup.asmx

Also, a lot of the google apis (maps, new) will turn zip codes into cities and other info (news, geo coordinates, etc).

Answer 3

geonames

http://www.geonames.org/export/web-services.html#postalCodeLookupJSON