What is a verification status in Hunter?
When searching for emails in Hunter, you'll find that many already have a verification status and a corresponding confidence score. This gives you an initial assessment of whether an email is likely to be safe to use.
An email address can have different email verification statuses which we can group into:
Valid: email addresses that can receive emails and can be used safely.
Accept all: email addresses that have email servers that accept any type of email sent to them. Using this type may lead to bounces. Click here for more information about accept all emails. 
Invalid: email addresses that can't receive emails, are inactive and shouldn't be used.
Disposable: email addresses which are temporary emails that shouldn't be used for cold outreach.
What do the possible verification statuses mean?
Valid
Valid means that this email address is active and can receive emails; you can safely use this email address.
Accept All
When an email address has an accept-all status (sometimes called catch-all), it means that the domain associated with the email has the policy to report any email on the domain as valid, so Hunter, or almost all verification tools, can't verify if the email is currently deliverable or not. More information on accept all emails can be found here.
Invalid
When an email address has status Invalid, it means it has failed the verification checks and it shouldn't be used since it doesn't exist or can't receive emails.
Disposable
A disposable email address is a temporary email that self-destructs after a certain timeframe.
Unknown
When an email address has a status Unknown, or Blocked it means that Hunter could not determine the validity of the email.
This usually happens when the domain linked to the email is grey-listing or blocking our verification process, preventing Hunter from validating the email address. To learn more, visit our help article on Why some email addresses can't be verified.
What status is applied to emails that haven't been verified yet?
All the emails found in Hunter without a validity status have a confidence score assigned which will provide you with a first overview of the likeliness that the email is valid. You'll find the score below the email in the Domain Search:
Email addresses with a confidence score of 90-95% or higher have a high chance of being fully deliverable, although a high score does not guarantee deliverability.
We strongly recommend verifying your leads before starting a campaign, to make sure your leads are valid and can receive emails. To verify existing leads you can run them through the Bulk Email Verifier or directly verify your leads in the Leads section.