I want to allow my users to add email recipients in a text area by simply writing their addresses manually or by copying and pasting them from somewhere; E-mail addresses are separated by a comma or a new line.
How to validate an email address?
If it is an incorrect address, let's say, john.doe @ example, comHow do you tell the user that it is wrong?
A) Show them a notification in the text area?
If you have several errors, you can always expand the notification below and make it scrollable.
SECOND) Offer a suggestion / notification?
This option would be very frustrating when the user has several errors.
DO) Do you offer any validation at all?
AFAIK, the email validation is not 100% accurate, regardless of what you do, you can never take into account all the vanguard cases. Therefore, you could end up creating a nuisance if you do not validate a legitimate email.