I wrote eMail Verifier and I have been using and developing the tool for years. As a developer and also a user I was very worried about deleting valid emails. So I created a system that only flags bad emails, I mean, when there is absolutely no doubts. If eMail Verifier is not 100% sure then the address is mark as 'Looks Good' or 'Looks Bad' and the user decides what to do. The software tries to clean the list its best but without taking any risk of deleting valid emails.
Yesterday, steveb-ci, an eMail Verifier customer posts a very interesting comment in our forum about eMail Verifier compared to online solutions. This is what it says:
I've been on a big test recently, comparing how well the various email cleaning services compare to each other.
I started with a list of 1500 emails that hadn't been used in several years. Email verifier reduced the list to 1275 addresses marked as OK, or looks OK.
I then ran the list of 1500 through some of the most popular online cleaning solutions, the most notable of which was Never Bounce, which came highly recommended.
Never Bounce reduced the list to 900. Interestingly Email Verifier tagged 350 emails as "looks OK", so I summised Never Bounced played it safe and even if the address "looked OK", it tagged it as bad.
The other services I tried ranged from 300-850 good emails.
I took the results of Email Verifier, 1275 emails and sent them a test email. 80 bounced, 19 hard bounces.
So in short, if I'd gone with the list from Never Bounce I'd have lost over 300 good emails. If I'd have gone with any of the other lists I'd have lost a lot more. Only Email Verifier got very very close to the correct number of good addresses.
The other thing to note is that only Email Verifier allowed me to export various different lists: Good. Looks like good, bad, or a mixture. All the online services would allow me to export was the good emails or all the emails.
It's been very time consuming and pretty expensive to run all these tests, but it's been very worthwhile, I can continue to use Email Verifier safe in the knowledge it delivers the best results.
Thought it worth sharing.
eMail Verifier actually checks every address from a given mailing list, using the same algorithm as ISP mail systems do, allowing you to determine up to 70-80% of "dead" mail addresses. Yes, up to 70-80%, there is no way to be sure at 100% and it is what the products page says by the way. eMail Verifier tries to connect to each mail server and simulates the sending of a message. Then it scans the server response very carefully. The algorithm used to clarify the responses is the result of years of testings.