• valid- These are emails that we determined to be valid and safe to email to, they will have a very low bounce rate of under 2%. If you receive bounces it can be because your IP might be blacklisted where our IP was not. Sometimes the email accounts exist, but they are only accepting mail from people in their contact lists. Sometimes you will get throttle on number of emails you can send to a specific domain per hour. It's important to look at the SMTP Bounce codes to determine why.
    • alias_address- (valid) These emails addresses act as forwarders/aliases and are not real inboxes, for example if you send an email to and then the email is forwarded to It's a valid email address and you can send to them, it's just a little more information about the email address. We can sometimes detect alias email addresses and when we do we let you know.
    • leading_period_removed- (valid) If a valid email address starts with a period '.' we will remove it, so the email address is compatible with all mailing systems.
    • alternate

      - (valid) These emails are valid, but they are likely to be secondary addresses for the users. Alternate emails are often used to sign up for accounts but otherwise do not see much engagement. As opposed to primary email addresses, which would look more formal, alternate emails will usually contain numbers or more special characters, e.g Identifying alternate email addresses allows for better email list segmentation. Users with formal emails are more likely to engage with your content.

  • invalid- These are the emails that we determined to be invalid. Please delete them from your email list. The email can be deemed as invalid for various reasons such as mailbox not found or the if address doesn't accept emails. Please see below a list of sub_status codes to help explain some of the invalid results.
    • does_not_accept_mail- (invalid) These domains only send mail and don't accept it.
    • failed_syntax_check- (Invalid) Emails that fail RFC syntax protocols.
    • possible_typo- (invalid) These are emails of commonly misspelled popular domains. These emails are marked invalid.
    • mailbox_not_found- (invalid) These emails addresses are valid in syntax, but do not exist. These emails are marked invalid.
    • no_dns_entries- (invalid) These emails are valid in syntax, but the domain doesn't have any records in DNS or have incomplete DNS Records. Therefore, mail programs will be unable to or have difficulty sending to them. These emails are marked invalid.
    • mailbox_quota_exceeded- (invalid) These emails exceeded their space quota and are not accepting emails. These emails are marked invalid.
    • unroutable_ip_address- (invalid) These emails domains point to an un-routable IP address, these are marked invalid.
  • catch-all- These emails are impossible to validate without sending a real email and waiting for a bounce. The term Catch-all means that the email server tells you that the email is valid, whether it's valid or invalid. If you want to email these addresses, I suggest you segment them into a catch-all group and know that some of these will most likely bounce.
  • spamtrap- These emails are believed to be spamtraps and should not be mailed. We have technology in place to determine if certain emails should be classified as spamtrap. We don't know all the spamtrap email addresses, but we do know a lot of them. Read our Guide to Spam Traps to learn more.
  • abuse- These emails are of people who are known to click the abuse links in emails, hence abusers or complainers. We recommend not emailing these addresses.
  • do_not_mail- These emails are of companies, role-based, or people you just want to avoid emailing to. They are broken down into 6 sub-categories "disposable","toxic", "role_based", "role_based_catch_all", "global_suppression" and "possible_trap". Examine this file and determine if you want to email these address. They are valid email addresses, but shouldn't be mailed in most cases.
    • global_suppression- (do_not_mail) These emails are found in many popular global suppression lists (GSL), they consist of known ISP complainers, direct complainers, purchased addresses, domains that don't send mail, and known litigators.
    • possible_trap- (do_not_mail) These emails contain keywords that might correlate to possible spam traps like spam@ or Examine these before deciding to send emails to them or not.
    • role_based- (do_not_mail) These emails belong to a position or a group of people, like sales@ info@ and contact@. Role-based emails have a strong correlation to people reporting mails sent to them as spam and abuse.
    • disposable- (do_not_mail) These emails addresses are temporary and become invalid after a set period. Avoid adding disposable emails to your list to avoid future bounces.
    • toxic- (do_not_mail) These email addresses are known for abuse and spam. They may also be bot-created emails. If any of your emails possess this flag, you shouldn't email them. We also provide other additional fields that you should take into consideration before emailing.
    • role_based_catch_all- (do_not_mail) These emails are role-based and also belong to a catch_all domain.
    • mx_forward - (do_not_mail) These emails belong to domains which are set up to forward their MX records into one single domain. Their use case is somewhat similar to disposable domains.
  • unknown- These emails we weren't able to validate for one reason or another. Typical cases are "Their mail server was down" or "the anti-spam system is blocking us". In most cases, 80% unknowns are invalid/bad email addresses. We have the lowest "unknowns" of any email validator, and we don't make this statement lightly. We paid and tested email lists at over 50 different validation companies to compare results. If you do encounter a large number of unknowns, please submit those for re-validation. Remember you are not charged for unknown results, credits will be credited back. If you still have a large number, contact us and we will take a look and verify.
    • antispam_system- (unknown) These emails have anti-spam systems deployed that are preventing us from validating these emails. You can submit these to us through the contact us screen to look into.
    • exception_occurred- (unknown) These emails caused an exception when validating. If this happens repeatedly, please let us know.
    • failed_smtp_connection- (unknown) These emails belong to a mail server that won't allow an SMTP connection. Most of the time, these emails will end up being invalid.
    • forcible_disconnect- (unknown) These emails belong to a mail server that disconnects immediately upon connecting. Most of the time, these emails will end up being invalid.
    • greylisted- (unknown) Emails where we are temporarily unable to validate them. A lot of times if you resubmit these emails they will validate on a second pass.
    • mail_server_did_not_respond- (unknown) These emails belong to a mail server that is not responding to mail commands. Most of the time, these emails will end up being invalid.
    • mail_server_temporary_error- (unknown) These emails belong to a mail server that is returning a temporary error. Most of the time, these emails will end up being invalid.
    • timeout_exceeded- (unknown) These emails belong to a mail server that is responding extremely slow. Most of the time, these emails will end up being invalid.

We also provide a sub_status code to help explain some of the unknown and invalid results, not all unknowns and invalids will have sub_status codes.

Other Fields

  • free_email- [true/false] If the email comes from a free provider.
  • mx_found- [true/false] Does the domain have an MX record.
  • mx_record- The preferred MX record of the domain.
  • smtp_provider- The SMTP Provider of the email or [null] (BETA).


As a responsible email validation service, we do our best to protect your IP/Domain Mailing Reputation. You mailing campaign becomes successful when you email lands in the inbox and not the junk box.

Just eliminating bounces is the first step to a healthy IP Reputation, but there are many more steps in the process. Read our Email Deliverability Guide.

The "Do Not Mail" Status represents one of the next steps where we identify potential emails that can cause harm to your IP/Domain Reputation.


Let's dig a little deeper into the meaning of role-based and why, but let's hear it from the mailing exports of major ESP Providers who send billions of emails a day. Click of the following links below.

There are hundreds of more links from many more large companies than the ones above explaining why. We totally understand that depending on your business model and industry. That you might need to email to role-based emails, that's fine, it's the risk you take. We're just pointing it out and it's your decision on which role-based emails you want to mail and the risk you want to take.

All emails that we flag as "Role-Based" are valid emails, they have been validated.