USPS Validation

I have a address form where the user can enter the residential and mailing address.
I have to validate the mailing address using the USPS tool web tool.  I have already registered for usps to start
using their service. I have no idea how to do this. Can some one tell me how do i go about. Can some give me a sample code or Book.

Anything will be appreciated?

 Thanks 

 

 

 
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