Understanding Validation Results

Result value

Our validation data have several parameters. For your convenience, for each email we additionally combine all of them into one simple value called "Result".

It can have one of five variants:
  • Safe
    You can safely send an email to this address.
  • Invalid
    You should not try to send emails to this address. It is either bounce or disposable.
  • Risky
    If an email is Catch-All or Role-based we mark it as Risky. See additional details and sending recommendations below.
  • Unknown
    We are unable to definitively determine this email’s status.
    If you have a dedicated email server with your own IPs, unknown emails are normally safe for sending.
    But if you use a third-party email provider that requires a bounce rate below 4%, these emails are not safe for sending.
  • Aborted
    This result occurs only when you abort a list validation process. We return to you the credits for all emails that we have not started validating yet and mark them as Aborted.

Detailed validation data

Also, we give you additional details about each email.

Deliverable detailDescription
Deliverable In this parameter we show the result of our communication with a recipient's mail server. It can have one of the following values:
  • Valid
    Valid means the recipient's mail server stated the recipient exists and the domain is not Catch-All.
  • Invalid
    This email does not exist or has a full inbox. Anyway, it is not deliverable at this moment.
  • Catch-All
    Some domains accept all emails you send to them, even if the email address does not exist. After an email is sent, the recipient's mail server may silently discard the message or send a bounce message. For such domains, we cannot guarantee an email will be delivered to a user's inbox. Sending to a Catch-All (also known as Accept-All) domain may increase your bounce rates and/or lower your open rates. Therefore, use a degree of caution when sending to Catch-All domains.
  • Unknown
    Null Bounce marks an email unknown 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. Retrying your request after about 5 minutes may in some cases return a valid or invalid response. Unknown addresses don't count against your verification credits: they are free for you.
DisposableDisposable emails are temporary addresses used to avoid using a real personal account during a sign-up process. Common providers of disposable emails include Mailinator, AirMail, Guerilla Mail, 10 Minute Mail. Don’t send – these emails are fake or temporary emails and are not safe for sending.
RoleRole-based email addresses (like info@, welcome@, sales@, leads@) are addresses that are not associated with a particular person, but rather with a company, department, position, or group of recipients. They are not generally intended for personal use and have a strong correlation to people reporting emails sent to them as spam and abuse. That's why we marked such emails as Risky (in case they are deliverable)
FreeEmail is marked free when its domain is supplied by a free email service provider like gmail.com, yahoo.com, etc. This parameter is not directly related to deliverability and is here just for your information. In certain contexts, businesses can receive better open/response rates when only sending to non-free email addresses.

Technical details about Deliverable

With regard to the "Deliverable" parameter, we provide you with additional details when this value is Invalid or Unknown. We give such information in brackets, like this: Invalid (No Smtp).

Deliverable detailDescription
For Invalid the possible variants are:
Failed Syntax CheckThe provided address is not syntactically correct
Mailbox Not FoundThis address does not exist
Mailbox Quota ExceededEmail address exists but the inbox is full, so it cannot accept emails.
No SmtpThere is no mail server, or even any MX record that is correct.
For Unknown the possible variants are:
Failed Smtp ConnectionThe mail server won't allow an SMTP connection. Most of the time, these emails will end up being invalid.
Forcible DisconnectThe mail server disconnects immediately upon connecting. Most of the time, these emails will end up being invalid.
GreylistedEmails where we are temporarily unable to validate them. Usually, if you resubmit these emails, they will validate on a second pass
Mail Server Did Not RespondThe mail server is not responding to mail commands. Most of the time, these emails will end up being invalid.
Mail Server Temporary ErrorThe mail server is returning a temporary error. Most of the time, these emails will end up being invalid.
Timeout ExceededThe mail server is responding extremely slowly. Most of the time, these emails will end up being invalid.
Antispam SystemThese servers have antispam systems that prevent us from validating their emails. You can submit these to us to look into.
ExceptionThese emails caused an exception when validating. If this happens repeatedly, please let us know.
Last Updated: 11/9/2021, 11:35:58 AM