title: Detecting valid and invalid email address
body: <p>Is there any way someone can check if the user is creating an account with a valid email address. I am trying to create an app, however, the user can register with any kind of data, even without using the valid email address. Can someone give me an idea, what should I use so that the error comes up if the email address is invalid or if the person is just typing text and not a valid email address. Also, what can I implement to detect if the person is trying to create an account with the used email address.</p>
  <p>Answer could be in theory or code. An example of code would be more helpful as it would help me to understand the concept better. Thanks in advance.</p>