When we migrated our existing patient “database” into Clinic Office we found we had 14 different spellings for “Maidstone.” So the integration with Postcode Anywhere to ensure that addresses are validated has been a key feature for us.
I now see that Postcode Anywhere has extended to offer Email address proofing (checks the syntax and the DNS). Furthermore it is free if you have address licences. There are some example scripts on how to link this into an application.
ClinicOffice already validates the form of email addresses to make sure they are in a correct format. If you try entering an invalid email address you should see that you are prevented from doing so. Is this what you mean?