Apollo only provides guessed emails when multiple pieces of evidence suggest a probable email. Apollo then marks the email as guessed and indicates the confidence level. Apollo only returns guessed emails if the confidence level is 50% and above.
To see the confidence rating of a contact's email, go to the contact's page and hover your mouse over the email icon.
This shows you how confident Apollo is in the email address.
Please note, you will not be charged an email credit for a guessed email. Only verified emails cost credits. For more information about how credits work in Apollo, refer to the What Are Credits? article.
Apollo recommends you use guessed emails with caution to keep your domain reputation safe. If you currently have a high bounce rate, do not send guessed emails through your sequences until you repair your reputation with your mailing service. For more on email bounce rates, please refer to the Why Do I See Such a High Bounce Rate for Emails from Apollo? article.
Hop on into the Email Status Overview article if you have more questions on the 5 types of email statuses in Apollo. Alternatively, if you are worried about your domain health and only want to search for contacts with verified emails, check out the Display People With Verified Emails article.