CMail Command Line Mailer

BETA testers needed for OAuth2 integration.

See CMail OAuth2 Builds if you are interested in testing CMail with OAuth2.

What is CMail? CMail is a freeware application that allows you to send e-mail from the Windows command line. It is primarily intended for sending e-mail from batch files or other scripts, but simple enough to be used interactively. If you are looking for an alternative to Blat with SSL support (stunnel not required), or more control over message formatting, CMail may be a good choice.

CMail is not intended to be a better Blat, it was developed to assist with testing mail server and content analysis software, and as such has evolved with a completely different feature set. While being very easy to use in its basic form, CMail provides advanced options for those who require them, allowing users to specify such things as the encoding mechanism for the message body and individual attachments, the types of authentication mechanisms to use, aliases for all recipients (similar software often doesn’t support aliases, or can only send to a single user), and per-recipient Delivery Status Notification settings. Users can also control various aspects of the SMTP session, including enforcing the use of SSL/TLS where security is a consideration, setting the HELO/EHLO, adding custom headers, and mandating the use of IPv4 or IPv6.


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  • Flexible configuration via files or the command line and optional GUI provided by CMailGUI.

  • TLS/SSL (including TLS 1.3) via STARTTLS or SMTPS (SSL-enabled version). Built-in, stunnel not required.

  • Support for adding multipart/alternative HTML message bodies (UTF-8) and embedded images.

  • SMTP authentication using CRAM-MD5, PLAIN, LOGIN and OAUTHBEARER.

  • Unlimited attachments using base64, quoted printable or uuencoding.

  • Wildcard attachment support to attach directory content.

  • Unlimited To/Cc/Bcc recipients, with aliases and DSN options for each if desired.

  • Message bodies using plain text, base64, or quoted printable encoding.

  • IPv6 support.

  • DKIM signing (RSA and Ed25519).

  • Delivery Status Notification and Message Disposition Notification (Read receipt) support.

  • Read message body from command line, stdin or file.

  • Sending via SOCKS or HTTPS proxies.

  • Works with GMail using App Passwords or user-supplied OAUTHBEARER tokens.

  • Written entirely in C - no need for .NET libraries, Java, or other prerequisites.

  • No installation required. Download, extract, use.

  • Free for private and commercial use.