Reoon Email Verifier is an amazing tool with an easy to use and clean UI. It verifies single and bulk emails and gives a detailed report as well as a csv file of valid emails. I get 2 modes to verify emails from its API - Quick Mode and Power Mode. Using Quick mode, emails can be verified quickly but the accuracy reduces but using Power mode, emails can be verified with 99% accuracy.

Pros:-
It identifies invalid emails with an accuracy of 97 - 99%.
Its user interface is very clean so even a non-techie user can use it easily.
It gives the result in less than 1 second with the highest accuracy even through API call.
Even a beginner user can easily use its API.
Customer support reply is also available in maximum 24 working hours.

I integrated it to automatically verify the email of leads that come to my website, so now I only get leads that have a valid email address. If the email is not valid the form just won't submit.

Using this tool we have been able to eliminate 99% of spam leads. I highly recommend this tool.