There are a few ways of validating email addresses. Firstly making an email field required will validate that the email address has been entered correctly. You can also add regex matching using the pattern setting.
As for checking if an email address is actually a real email address, we’ve tried that in the past and found that it could not be done reliably enough. For example, catch all email address etc are not verifiable using this method.
Email validation is typically done by sending a partial SMTP request but then you reset connection before the email is sent.
We therefore opted not to include that feature in WS Form because it potentially rejects valid email addresses.
If anyone else has any ideas on how email addresses could be reliably verified we’re open to ideas!