Formatted string used to specify a standard electronic mail message, formatted name@addess.domain. This is defined in RFC 2822 (and some definitions in RFC 2821). It consists of a local part and a domain part separated by the character '@' Note that RFC defines several forms of email address that are fairly rare. Valid email addresses someone@example.com a.someone@example.com a.one_two{}@some.example.com !def!xyz%abc@local.example.com some..one@example.com Invalid email addresses .someone@example.com someone.@example.com @example.com Possibly valid email addresses that fail validation some\@one@example.com someone@b.com someone@example.longdomain This pattern does not cover valid cases like quoted local parts, escaping, character sets other than ASCII, IP address, domain roots (.com) longer than 9 characters and less than 2 and several other cases