Username and group name guidelines
When choosing usernames for users and groups you add to your Google Cloud account, consider the following guidelines:
Usernames can contain letters (a-z), numbers (0-9), dashes (-), underscores (_), apostrophes ('), and periods (.).
- Usernames can't contain more than one period (.) in a row, accents, accented letters, ampersands (&), equal signs (=), brackets (<,>), plus signs (+), or commas (,).
- Usernames can begin or end with non-alphanumeric characters except periods (.), with a maximum of 64 characters.
- First and last names support unicode/UTF-8 characters, with a maximum of 60 characters.
Group names can have a maximum of 60 characters.
Group description and group name can’t contain an equal sign (=), or brackets (<,>).
Note: Periods (.) are not ignored as they are in a gmail.com account. If you create a user account called username, this user will not be able to receive messages addressed to user.name, or us.er.na.me, or any other combination of periods. To let a user receive mail with these variations, create an email alias for them.
Because abuse and postmaster are reserved aliases, you can't use them as usernames or aliases. Learn more
Read more about creating strong passwords.