Email validation status codes

When completed, email validation snapshots bring one or more validation entries along with their email validation statuses. Verifalia defines several different statuses, where every value signals a successful validation or a particular issue.

Generic status codes

  • Success

    Email address verified successfully.


Syntax status codes

  • UnmatchedQuotedPair

    A quoted pair within a quoted word is not closed properly.

  • UnexpectedQuotedPairSequence

    An unexpected quoted pair sequence has been found within a quoted word.

  • InvalidWordBoundaryStart

    A new word boundary start has been detected at an invalid position.

  • InvalidCharacterInSequence

    An invalid character has been detected in the provided sequence.

  • UnbalancedCommentParenthesis

    The number of parenthesis used to open comments is not equal to the one used to close them.

  • DoubleDotSequence

    An invalid sequence of two adjacent dots has been found.

  • InvalidLocalPartLength

    The local part of the e-mail address has an invalid length.

  • InvalidFoldingWhiteSpaceSequence

    An invalid folding white space (FWS) sequence has been found.

  • AtSignNotFound

    The at sign symbol (@), used to separate the local part from the domain part of the address, has not been found.

  • InvalidEmptyQuotedWord

    An invalid quoted word with no content has been found.

  • InvalidAddressLength

    The email address has an invalid total length.

  • DomainPartCompliancyFailure

    The domain part of the email address is not compliant with the IETF standards.


DNS status codes

  • DomainDoesNotExist

    The domain of the e-mail address does not exist.


SMTP status codes

  • SmtpConnectionTimeout

    A timeout has occured while connecting to the mail exchanger which serves the e-mail address domain.

  • SmtpConnectionFailure

    A socket connection error occured while connecting to the mail exchanger which serves the e-mail address domain.


Mailbox status codes

  • MailboxDoesNotExist

    The mailbox for the e-mail address does not exist.

  • MailboxConnectionFailure

    A connection error occurred while validating the mailbox for the e-mail address.

  • LocalSenderAddressRejected

    The external mail exchanger rejected to accept messages from Verifalia.

  • MailboxValidationTimeout

    A timeout occured while verifying the existence of the mailbox.

  • MailboxTemporarilyUnavailable

    The requested mailbox is temporarily unavailable (perhaps it is over quota). Please note that Verifalia validates email addresses in multiple passes and every temporary condition is checked for up to 20 minutes before having this status applied.

  • ServerDoesNotSupportInternationalMailboxes

    The external mail exchanger does not support international mailbox names, while the supplied address pretend to have one.

  • MailExchangerIsHoneypot v1.2+

    The external mail exchanger hides a honeypot / spam trap.


Catch-all status codes

  • CatchAllValidationTimeout

    A timeout occured while verifying fake e-mail address rejection for the mail server.

  • ServerIsCatchAll

    The external mail exchanger accepts fake, non existent, e-mail addresses; therefore the provided e-mail address MAY be inexistent too.

  • CatchAllConnectionFailure

    A connection error occurred while verifying the external mail exchanger rejects inexistent e-mail addresses.


Duplicates removal / scrub status codes

  • Duplicate v1.4+

    The email address appears to be duplicated with another entry which appears previously in the same validation job. The duplicateOf value contains the zero-based index of the first occurrence of the address within the list.




Not a software developer?

Verifalia is a web-based email validation service which allows to upload and validate lists of email addresses with ease.


You don't need to be a software developer to use Verifalia! Just upload your list of email addresses and we will validate them for you, giving you back a detailed report.


Download the Verifalia SDK

To ease integrating Verifalia with your own software solutions, we are developing helper libraries that you can just download and plug where email validation is required. Validating an email address via Verifalia typically requires a couple of lines of code!

Microsoft .NET SDK

Free and open source helper library, C# language, VS 2015 solution, which allows to integrate Verifalia with other .NET 4.5 and higher solutions. Nuget package available!



Node.js SDK

Free and open source helper library which allows to integrate Verifalia with Node.js applications.



PHP SDK

Free and open source helper library which allows to integrate Verifalia with PHP applications.



Ruby SDK

Free and open source helper library which allows to integrate Verifalia with Ruby applications.



Java SDK

Free and open source helper library which allows to integrate Verifalia with Java applications.