How can I get state and city information from a US zip code through an online web service?

Question

I want to be able to give a best guess for what city and state a zip code is in via a web application. Is there some web service I can use to figure this out?

Answer 1

The USPS has an API for this, but you have to register:

USPS Web Tools

Answer 2

These people seem to expose one...

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

Answer 3

Hate to do this to you, but look here...

I believe the USPS has an API for some queries, you should look into that.

However, here are a few from the above resource:

• http://www.cedar.buffalo.edu/AdServ/zip-search.html - Includes the database so you can host one yourself
• http://www.zipinfo.com/search/zipcode.htm - commercial site, but they have a simple search
• http://zip4.usps.com/zip4/citytown_zip.jsp - USPS interface, probably has an API
• http://www.webservicex.net/uszip.asmx?op=GetInfoByZIP - SOAP interface

Answer 4

You can get a database that maps zip code to longitude/latitude, and another database that provides longitude/latitude for all US cities. Then you could just do that on your side, without having to send out to a web service.

I've seen both these databases, but I can't remember where to find them right now. I'll poke around and try to remember to add a comment.