Frequently Asked Questions
Does MailTester send an email to verify an address?
MailTester does not send any email to check the validity of an address.
We are just using queries sent to SMTP servers to test the validity of an email address.
Those commands where defined in 1982 by he Internet Engineering Task Force under RFC 821. You can find them here.
Can your site check all email addresses?
No, some SMTP servers do not authorize to verify an email address by sending an SMTP command or will just respond OK to any valid or unvalid tested email address.
We notify you of email addresses that cannot be tested with this icon: 
About 35% of email addresses cannot be tested.
On the 65% of all email addresses we can test, about 50% are unvalid. By removing them from your mailing list of from you recipients, you will save 4g of CO2 equivalent for each email you are trying to send.
Are you storing the submited email addresses?
No, we retain no information or email address submitted on our server.
Do you share my email lists or use them in any other way?
No, none of your checked emails are stored at our server side.
Are you storing any personal information?
We are not storing any single data about your visit, as our server do not use any database.
We also dot not use any cookies, so you won't need to click one more time on the stupid GPDR "Accept/Reject All" button, attached to the stupid endless consentement details you will never read!
Is GPDR totaly stupid?
Yes, thanks to our bravest bureaucrats, we've polluted every website on the planet with useless consent data that a human being can't read without superpowers.
Here we are offering a solution to avoid sending useless emails and saving some CO2 equivalent, while some idiots are adding a useless colossal amount of data on the internet.
How to reduce emails environmental impact?
Reduce the size of attachments, for example by compressing images or sending a hyperlink instead of a document
Unsubscribe from all unnecessary newsletters and subscriptions
Do not keep old e-mail addresses in which unread mails pile up
Reduce the list of recipients to what is strictly necessary
Regularly sort your mailbox and eliminate all unnecessary messages
Use an application that cleans your mailbox