PGYou can follow this tutorial: https://www.ethereum.org/tokenComment·Thread·Oct 17, 2018·How do I create my own cryptocurrency on top of Ethereum?
PGThe backend will check for the uniqueness of the email throw a response 409 or 422 (if you are dealing with REST). That way your UI will receive those error codes and show the appropriate error.Comment·Thread·Oct 11, 2018·"E-mail address already been taken" is responsibility of validator library or UI?