Here is the list of valid and invalid email format which can be used for testing. The list is not comprehensive by any means and is probably missing a bunch of edge cases. However, it provides enough coverage for the majority of the allowed/disallowed email address according to RFC 2822 . BTW, if anyone else would like to contribute more cases to this list, or spot errors (fingers crossed), please feel free to let me know and I'll make sure the list is up-to-date. Valid Email address Reason email@domain.com Valid email firstname.lastname@domain.com Email contains dot in the address field email@subdomain.domain.com Email contains dot with subdomain firstname+lastname@domain.com Plus sign is considered valid character email@123.123.123.123 Domain is valid IP address email@[123.123.123.123] Square bracket around IP address is considered valid "email"@domain.com Quotes around email is considered valid 1234567890@domain.com Digits in address ar