Once implemented our USPS address validation API checks addresses at the point of entry, instantly correcting any transposed numbers, misspelled street names, or missing information. A cleansed address not only assures accurate Sales & Use Tax calculations, it ensures deliveries are on time and correct, invoices are sent to their intended recipient and are paid, and your marketing mailings reach their audience.
For detailed documentation and samples see SimpleTaxService - Version 2009-12-20 API
Overview 
OVERVIEW
Once implemented our USPS address validation API checks addresses at the point of entry, instantly correcting any transposed numbers, misspelled street names, or missing information. A cleansed address not only assures accurate Sales & Use Tax calculations, it ensures deliveries are on time and correct, invoices are sent to their intended recipient and are paid, and your marketing mailings reach their audience.
For detailed documentation and samples see SimpleTaxService - Version 2009-12-20 API