Wishpond uses SMTP protocol to verify the email addresses because it allow us to determine if the recipient’s domain exist, if there is a mail server associated with that domain and much more, without actually sending an email to the recipient. (We don’t send an email to the recipient at any stage of the verification).

during the verification process we use some other approaches to make sure you get rid of all the dud emails that may ruin your sender reputation, during this approach we use the following :

Email de-duplication - domains that match our existing database of invalid emails are removed
Domain validation - DNS entries for every email address is checked and validated
Spam-trap removal - Spam-traps and disposable emails are detected
Risk validation - Remove all the domains that match our existing database of invalid emails
Syntax verification - Email addresses syntax are verified according to IETF standard
MTA validation - Checks if a Mail-Transfer-Agent has a valid MX Record

A deliverable result means the recipient's email is valid. Bounceless determined this address is safe to send to within our 95% Deliverability Guarantee.


An invalid email means the email address does not exist, for one of the reasons you get in the validation report(please check next section: Detailed result guide)

Accept All

Email address that always return a valid status, but from some domains that accept all email you attempt to send to them. Typically, these domains are trying to protect their legitimate users by telling the sending mail server it will accept the mail for a given email address, but then silently discard the message or send a bounce message after the fact.


Disposable addresses are created to be Valid only temporarily so their owners can sign up for promotions or services without using a primary address. Disposable addresses will not perform and typically just take up space in your database.


Bounceless will return an unknown result when it was unable to get a response from the recipient's mail server. This often happens if the destination mail server is too slow or temporarily unavailable. In some cases, retrying your request after about 5 minutes will return a valid or invalid response. Unknown addresses don't count against your verification balance.


Spamtraps addresses are created not for communication, but rather to lure spam. In order to prevent legitimate email from being invited, the e-mail address will typically only be published in a location hidden from view such that an automated e-mail address harvester (used by spammers).

Email Code Descriptions

When you import a list of emails into Wishpond, you will see a message indicating how many leads were imported successfully and how many were not:

If you click on the "invalid" text, a CSV with the invalid emails will be automatically downloaded for you to review. Each invalid email will be given a code. An explanation of each code is below.


all is ok : of catch all emails is when the server is saying that it is ready to receive a letter to this address, and no trickshave been detected

ok_for_all: email server is saying that it is ready to accept letters to any email.

antispam_system: some anti-spam technology is blocking the verification progress.


error - server: is saying that delivery failed, but no information about the email exists

smtp_error: SMTP answer from the server is invalid, destination server reported an internal error to us.

smtp_protocol: destination server allows us to connect, but SMTP session was closed before the email was verified.

unknown_email: server saying that delivery failed, and the email does not exist.

attempt_rejected: delivery failed, reason similar to “rejected".

relay_error: delivery fail because a relaying problem took place.

email_disabled: email account is suspended/disabled/limited and can't receive emails.

domain_error: email server for the whole domain is not installed or is incorrect, so no emails are deliverable.

dead_server: email server is dead, no connection to it exists.

syntax_error: syntax error in email address.

unknown: email delivery failed, but no information about why.
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