I’m working on setting up an e-mail service.
Is there any advice on characters to allow in usernames?
I know there are some wacky characters that are legal in e-mail addresses but are generally frowned upon – like
is apparently a legal address – but I know I don’t want to allow ampersands and brackets etc. in an address.
I don’t think a whitelist alphabet is best approach because of people with names that are not spelled with Latin characters.
Is there an existing blacklist of characters that technically legal but are generally avoided in e-mail addresses?