Make this your first defense against acquiring and storing inaccurate data. This service validates the area code and prefix (the NPA and NXX) of all the North American Dialing Plan range of phone numbers. In addition to verifying the validity of a phone number, this service will also return each zip code where this NPA/NXX combination exists. It also will give you the number of active phone numbers in each of these ZIP codes, as well as additional demographic information. These databases are updated every 30 days to ensure the most accurate data available.