emailrep.io is a simple tool with a nice API that will tell you information about an email address, including:
Reputation Level
Is it suspicious?
References
Is it blacklisted?
Has its credentials been leaked?
Has it been part of any data breach?
Is it a spammer?
Is it spoofable?
And much more. A further description from their website states:
As this is posted in pentesting, some of the offensive usecases of this tool might include:
Conduct recon on a target to prepare for credential bruteforcing
Constructing targeted phishing attacks
Avoid the spam folder
There are also defenses ways in which this tool might be used, like to detect phishing attacks, prevent fraud, require additional layer of verification during registration, etc.
Check it out!
Link to site: https://emailrep.io/