Gammadyne Corporation
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Rated 5/5 stars on
"If you're looking for an email client with some punch and a good spread of features, this may be exactly what you need."
- M. Callahan
"A vast improvement over Microsoft Mail."
- Ken McVay
"It provides excellent functionality, a clean appearance, and easy customization.  Wonderful job!"
- Eric Wilson


Clyton is a full-featured Windows email client with advanced security and spam filtering capabilities.  This is a must-have program for anyone who needs to keep their email private, or anyone swamped with spam.  Although priced for the general public, Clyton possesses the reliability and security required by large companies.

New visitors are encouraged to read the review by Doctor File Finder.


Security is Clyton's top priority.  We've worked tirelessly to make Clyton the most secure email client available.

Connection Security

  • Connections to the mail server can be secured with SSL/TLS encryption.  This prevents an eavesdropper from reading your mail.
  • Mail server passwords are verified using the NTLM, DIGEST-MD5, or CRAM-MD5 method, which is able to confirm the password without ever transmitting it.  This prevents an eavesdropper from intercepting the password.
  • Supports DomainKeys and DKIM signing and verification.  This ensures that an email has not been tampered with, and that the sender has not been forged.

Internal Security

  • All passwords are internally stored with encryption to ensure that they cannot be exposed, even to a user with admin rights.
  • Stored messages can be encrypted to prevent them from being read by programs or persons who have access to the file system.
  • Mailboxes can be password protected.  This prevents mail from being read or composed even if physical access to the computer is compromised.
  • The Address Book can be password protected.
  • Sensitive messages can be shredded in such a way that no forensic recovery is possible.

Virus Security

  • Until permitted, HTML email is restricted from running scripts, loading embedded objects, and downloading media.  Malware cannot infect the computer simply by viewing an email.
  • The Address Book is encrypted to prevent malware from spreading to your contacts.
  • You are warned before opening potentially dangerous attachments.
  • Clyton is compatible with third-party anti-virus email scanners.

Spam Filter

Clyton's spam filter is second to none.  Expect 85% of spam to be eliminated with the default configuration.  Using "fuzzy logic" techniques, email is not considered spam unless the penalties exceed an adjustable threshold.  By increasing the sensitivity, even higher detection rates can be achieved.


  • DNSBL blacklist testing is fully supported.  Spamhaus is the recommended blacklist, as it is very high quality and well maintained.
  • Email that is suspicious but not obviously spam is quarantined for 24 hours, then retested.  This greatly improves the effectiveness of blacklisting because it prevents spam from slipping through before the blacklist has a chance to notice.
  • Every server that the email is routed through is tested for blacklisting.
  • Every hyperlink in the email body is tested for blacklisting.


  • There are 21 stock rules that help identify spam.  Chinese spam and image spam are almost always detected by these rules.
  • A table of over 450 custom rules comes pre-configured to identify spam.  For example, an email can be penalized for having a hyperlink to a certain type of file, such as an EXE.  You can add your own rules to this table.


  • A "Curse" is a short phrase that adds a penalty to an email's spam score.  "Viagra" and "get rich quick" are examples.
  • Over 1200 curses are preconfigured.  You can easily add your own curses as well.
  • Clyton can recognize many character substitutions when detecting curses.  For example, substituting "@" for A or "!" for I or L will not fool Clyton.

Key Features

  • Clyton can be installed to a USB flash drive (a.k.a. thumb drive, memory stick).  This allows you to run Clyton from any computer.
  • Built-in address book supports custom fields and import/export.
  • Send personalized mass mail to a filtered set of address book contacts.
  • Supports text search in a single folder or globally.
  • Whitelisting prevents false positives by the spam engine.  Address book contacts and whitelisted senders are never treated as spam.
  • Allows full control over the compose/reply/forward templates.  This is especially useful for putting your business details below the signature.
  • Message drag & drop supported.
  • Attachment viewer supports a wide variety of image formats, HTML, PDF, and MIME.  Images can be zoomed in and out.
  • Multithreaded design keeps the user interface responsive.  Receiving, sending, and spam checking are performed in the background by worker threads.
  • Compose email formatted in HTML with a powerful editor.  Includes spell-checking.
  • Supports both POP3 and IMAP4 mail server protocols.

Additional Features

  • Messages can be organized in folders and color coded.
  • Multiple messages can be selected with the Shift and Ctrl keys.  The following features can operate on multiple messages:  Delete, Forward, Redirect, Save, Shred, Drag & Drop, and Color Coding.
  • Old messages can be automatically deleted (by age or count) from the Trash and Spam folders.  This prevents the hard drive from filling up with old emails.
  • Attachments can be automatically included in newly composed messages.  This is great if you have a vCard.
  • Reminds of birthdays and anniversaries.
  • Skinnable, zoomable, highly configurable user interface.
  • It is possible to automatically insert a random famous quote below your signature.
  • Most of Gammadyne Mailer's G-Merge language is supported in templates, mass mailings, and an Incoming Script.  The Incoming Script runs each time an email is received.  It can modify messages, move them to different folders, control deletion, autorespond, influence spam checking, and much more.


Click the button below to download Clyton version 14.0, released September 7th, 2016.

The download is a time-unlimited trial with some nonessential features disabled.  To unlock these features, please purchase a license.

  • The download is a self-contained executable installer.  Simply open the file to begin installation.
  • The download is approximately 16 MB and installation will use approximately 57 MB of hard disk space.
  • If you prefer to download the installer inside of a .zip file, click here.
  • To update an existing installation, simply install the new version over the old one.


A POP3 or IMAP4 email account is required.  Clyton does not work with web-based email accounts unless they support POP3 or IMAP4.  It does work with Gmail,, and Yahoo! Mail.

Clyton runs on the Windows 10, 8, 2012, 7, 2008, Vista, XP, 2003, and 2000 platforms.


To purchase a license for only $25 U.S. please click the button below.