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Email Sources

Email addresses with a public source link are marked with a globe icon. This means that we have found this email address on a publicly available website. The website can be viewed by clicking on the icon.


Email addresses without globe icons are approximated using other email addresses where a public source link is available. An example: If we know that a person by the name of Elizabeth Johnson works for the same company as Martin Mustermann, we derive the email address as follows:

Email Validation

All contact-related email addresses are validated. We conduct several tests throughout this validation process to determine whether or not an email address actually exists.

This is an ongoing process, which means that contact-related email addresses will be automatically revalidated every 4 – 6 months.

The different validation statuses are displayed in our tools as follows:

Email address display

Validation Status

What does this mean?

valid ❓ We received a positive and trustworthy response from the mail server for this email address.

📧 Emails arrive with high probability.

unknown ❓ For some email domains*, the mail server returns a positive response for any e-mail address – even if it does not exist (= “catch all” configuration). Therefore, we also check modified forms of the tested e-mail address, e.g. If we get a positive result for email addresses that clearly do not exist, then the mail server has such a catch-all configuration.

📧 We do not know for certain if these email addresses truly exist.

unreachable ❓ This email address no longer exists or cannot receive e-mails for other reasons.

Info: An unreachable email address will only be displayed, if a source link was found online.

📧 Emails are likely to bounce.

[empty]  – ❓ Either no email address pattern was found to be able to derive a valid email address or

the email address that has been derived from a company-related email pattern turned out to be unreachable and therefore won’t be displayed.

*Email domain: is the last part of the email address starting after @ (e.g. , ,