Three checks can be performed to verify email addresses without actually sending emails to the recipients. These are syntax, domain and server level checks Syntax is probably the easiest to understand. If the format of an email address is invalid it will throw a syntax error. It’s easy to sort these invalid emails out even before connecting to the Internet.

Domain and server level checks require a connection to the Internet. They basically check if the domain name is valid and if a mail server is available to process incoming email messages.

The email verification software Realva Email Verifier can import email addresses in various ways. It supports pasting multiple email addresses in its interface but can also load a list of email addresses from a file.

It is then possible to verify all available email addresses by selecting one or all of the email verification checks. The software uses multiple threads which speeds up the process noticeably.

Another interesting aspect is that the email verification software will test the email addresses using a HTTP web server that is using a different port than 25. Port 25 is often blocked by organization, businesses or ISPs to block spam.

The verified email addresses can be sorted in various ways before they can be saved in formats such as txt, Excel, Word or csv.

The settings contain options that include changing the number of connections, using specific DNS servers or creating rules that mark emails as valid or invalid.

Realva Email Verifier is a sophisticated program for users who check email address lists regularly. It is compatible with most Microsoft operating systems.

Update: The email verification software is no longer available. The developer website returns a 404 not found error. The link has been removed as a consequence.