Welcome to BulkVerifier, an efficient multi-threaded application for checking e-mail addresses and domain availability. Quickly and easily verifies email addresses, huge domains and clean up your mailing / domain list. A powerful advanced bulk domain and email validation tool.

BulkVerifier v2.2 (New version!) offers you two processing modes fast and deep.

In its fast mode BulkVerifier works extremely fast being able to process mailing lists containing dozens of millions of e-mail addresses at a speed of several thousands addresses per second. This mode does not ensure the highest accuracy of checking/cleaning but is optimal by expended time and traffic and provides quite sufficient results. We recommend the fast processing mode of BulkVerifier as a high-speed tool for sifting obvious rubbish out of large mailing lists containing millions of e-mail addresses.

In its deep mode (default), BulkVerifier works significantly slower but provides much more precise results. Optimal data amount for this mode is 70...100 thousand e-mail addresses. We recommend the deep processing mode of BulkVerifier as a slow but high-quality tool for checking of not very large mailing lists.

Deep (slow) mode of BulkVerifier

In the deep (slow) mode BulkVerifier performs a complete two-stage check of e-mail addresses availability. To switch to this mode please check the option Advanced e-mail check using SMTP in the Bulk Verifier Options dialog (see also the section BulkVerifier interface and options).

The first stage of the check is absolutely the same as the one used by the fast mode of Bulk Verifier: the application extracts the mail server address of an e-mail address out of DNS.

If the mail server address is extracted successfully, the second processing stage starts. Bulk Verifier attempts to connect to this mail server and emulate a message dispatch. No message is actually sent during the e-mail availability check. BulkVerifier establishes the connection with the mail server, sends a hello message, transmits the sender’s address (Options\Sender) to pretend there is a message and then transmits the addressee’s mail box address (an e-mail address being checked). As soon as the receiving server confirms or denies the requested mail box availability, this domain / email validation tool disconnects.