Verify Catch-all emails and get results as “Catch-all pass” or Catchall-fail”

Traditional verification methods can not verify catch-all domains. That’s why we have developed our own catch-all service (CAV). Utilising a combination of traditional verification and email technologies, we have built a system to verify the deliverability of catch-all domains.


Our CAV solution is designed to work in conjunction with our industry leading B2B batch API so when a file is sent for validation, we will firstly carry out the traditional verification check and the results will come back as OK, Bad and Unknown (along with the relevant additional statuses). Once these results have been received and processed, then the catch-alls from the standard verififcation Unknowns will be sent off for the second enhanced clean automatically and a second results file for this will be returned to you with CAV result statuses as per the table below.
StatusAdditional StatusExplanation
CatchallPassNoBounceReceivedA status of NoBounceReceived means we received no soft or hard bounce messages from the target mail server and therefore we assume the mailbox is valid.
CatchallPassUnsubscribedDuring verification, we processed and stored a positive unsubscribe from the email address.
CatchallPassOpenedDuring verification, we processed and stored a positive open tracking from the email address.
CatchallPassAutoResponseReceivedAutoResponseReceived is as a result of a positive automated response being received from the target email address or mailbox. Usually, this will include "out of office" type auto-replies that provide confirmation that the mailbox is valid.
CatchallFailBadSyntaxThe syntax of the email address has been pre-screened and determined to be incorrectly formatted or not conforming to the RFC governing email address formatting.
CatchallFailHardBounceHardBounce means we have received a definitive response from the target mail server, such as “Email Address Does Not Exist” These emails are BAD. We recommend that you do not email to these addresses.
CatchAllRiskyInconsistentBounceInconsistentBounce means we have received multiple responses from the target mail server. These emails are potentially OK, but should be treated with caution! We recommend you introduce them gradually into your mailing list.
CatchallRiskyHistoricUnsubscribedWe have previously processed and stored a positive unsubscribe, so for compliance reasons we are not able to verify the email address any further.
CatchallUnknownSoftBounceSoftBounce means the target mail server has strict anti-spam techniques in place and refused to allow a connection. These emails are potentially OK, but should be treated with caution! We recommend you introduce them gradually into your mailing list.

We Can Verify Office 365


Office 365 mail servers are mostly catch-all, therefore unverifiable by other services. However, the Email Checker CAV system is optimized to fully verify Office 365 emails. We are the only provider able to do this.


Furthermore, some Office 365 servers are not catch-all but respond with false “OKs” for emails that are in fact invalid. Our CAV system double checks all Office 365 OKs to make sure they are truly valid.


To learn more about our CAV (Catch All Verification) service, simply get in touch via the button below. FIND OUT MORE