US Address Validation (Zip+4)

Question

I have a database that has a list of zip codes which has latitude, longitude, state, city, state fips code, time zone, etc. I'd like to extend this and write either a C# function or TSQL (SQL Server 2008) function that will take a street, city, state and zip and return the zip+4. I've searched high and low and there's many programs out there that can do it but none appear to actually allow me to see what they've done and enhance it for my own needs. Does anyone know of an open source solution that can do this or point me in the right direction so I can make an open source version?

Cruciferous

Answer 1

Possibly the easiest solution to use is the USPS's address API (http://www.usps.com/webtools/htm/Address-Information.htm#_Toc131231396) The usage regarding scrubbing databases is a bit vague (and if you ask them about it, it seems they remain just as vague, perhaps on purpose) but once you get approved it's VERY easy to send the data you have and get back a fully verified, 100% compliant and up-to-date address. Once you get the data back from USPS, you can simply add/subtract/agument it as you need prior to stuffing back into the DB. For instance, you could Geocode from the verified address, or from your DB, then append that data into the data you received, inserting in a loop.

I'm using it on one of my applications to validate inbound inquiries and it has proven nearly 100% reliable for getting me what I need corrected.

Youngling

The USPS API is an XML-based web service -- both sending and receiving. It's pretty quick, too. – Stiffnecked

The TOS allow use of their service as long as you're doing the validation for the purposes of mailing via the USPS. – Hinny

Answer 2

One thing to note about the USPS free API is that their license says the data it returns must be used only for sending things via the USPS. We had a need for ZIP+4 data but we ship our stuff through other carriers, so this meant we could not use the free service.

Concrescence

A careful reading of the USPS agreement shows that it doesn't allow wholesale cleaning of your address data, but does allow you to clean data incoming from webforms -- regardless of how it may be used in the future. – Stiffnecked

Eh, "User agrees to use the USPS Web site, APIs and USPS data to facilitate USPS shipping transactions only. [27 Jan 2012]" is pretty clear. – Hinny

Answer 3

I work for a company called SmartyStreets; we do postal address validation and are CASS-Certified by the USPS. However, there aren't license restrictions like with the USPS' API and Google's API and others. We even have a free version.

You'd be interested to try LiveAddress... and if you have any questions I'll help you implement it.

Hinny