For customers that need to process an entire list, database, or spreadsheet of US addresses we recommend the SmartyList tools. Most users with spreadsheets will find the web interface fast and easy to use. For users with much larger lists (with more than 50,000 addresses) we recommend the command-line interface, which requires familiarity with a terminal/command prompt.
Both interfaces process lists of addresses via the US Street Address API. The Web Interface also processes lists of city/state/zipcode combinations via the US ZIP Code API and international addresses via the International Street Address API.