neatmail is a noninteractive mail client. It generates a listing of the messages in a mailbox in mbox format and executes a list of ex-like commands on it.

This package provides an Emacs-based interface to the Notmuch mail system.

TNEF is a tar-like program that unpacks MIME attachments of type application/ms-tnef.

The osmtpd API is an event-based C programming interface for writing OpenSMTPd filters.

The RSS2email program (r2e) fetches RSS/Atom news feeds, converts them into emails, and sends them.

The filter-dkimsign OpenSMTPd filter signs outgoing e-mail messages with DKIM (RFC 4871).

mpop is a small and fast POP3 client suitable as a fetchmail replacement.

mpop supports multiple accounts, header based mail filtering, delivery to mbox files, maildir folders or an MDA, TLS/SSL, several authentication methods, IDN and SOCKS proxies.

isync/mbsync is a command-line tool for two-way synchronization of mailboxes. Currently Maildir and IMAP are supported types.

Mlmmj is a simple and slim mailing list manager (MLM) inspired by ezmlm. It works with many different Mail Transport Agents (MTAs) and is simple for a system administrator to install, configure and integrate with other software. As it uses very few resources, and requires no daemons, it is ideal for installation on systems where resources are limited. Its features include:

1. Archive, Custom headers / footer,

2. Fully automated bounce handling (similar to ezmlm),

3. Complete requeueing functionality, Moderation functionality, Subject prefix,

4. Subscribers only posting, Regular expression access control,

5. Functionality to retrieve old posts, Web interface, Digests,

6. No-mail subscription, VERP support,

7. Delivery Status Notification (RFC1891) support,

8. Rich and customisable texts for automated operations.

afew is an initial tagging script for notmuch mail. It provides automatic tagging each time new mail is registered with notmuch. It can add tags based on email headers or Maildir folders and can handle spam and killed threads.

aerc is a textual email client for terminals. It features:

1. First-class support for using patches and git send-email

2. Vi-like keybindings and command system

3. A built-in console

4. Support for multiple accounts

Sieve-connect lets you view, upload, edit, delete, and otherwise manage Sieve scripts on any mail server that speaks the ManageSieve protocol, as specified in RFC 5804.

Sieve (RFC 5228) is a specialised language for e-mail filtering. Sieve scripts are stored on the server and run whenever mail arrives. They can automatically sort new messages into folders, silently reject them, send an automated response, and more.

sieve-connect is designed to be both a tool which can be invoked from scripts as well as a decent interactive client. It supports TLS for connection privacy, as well as authentication with SASL or GSSAPI client certificates. It should be a drop-in replacement for sieveshell from the Cyrus IMAP project.

Mew (Messaging in the Emacs World) is a user interface for text messages, multimedia messages (MIME), news articles and security functionality including PGP, S/MIME, SSH, and SSL.

This package implements a functionality to translate standard protocols (SMTP, IMAP, CardDAV) into ProtonMail API requests.

This package contains libraries and templates for Django-based interfaces interacting with Mailman.

GNU Mailman is software for managing email discussion and mailing lists. Both users and administrators generally perform their actions in a web interface, although email and command-line interfaces are also provided. The system features built-in archiving, automatic bounce processing, content filtering, digest delivery, and more.

The hyperkitty Django app provides a web user interface to access GNU Mailman3 archives, and manage it. This interface uses django, and requires some configuration.

dovecot-libsodium-plugin provides a libsodium password hashing scheme (such as scrypt) plug-in for Dovecot.

Swaks is a flexible, scriptable, transaction-oriented SMTP test tool. It handles SMTP features and extensions such as TLS, authentication, and pipelining; multiple versions of the SMTP protocol including SMTP, ESMTP, and LMTP; and multiple transport methods including unix-domain sockets, internet-domain sockets, and pipes to spawned processes. Options can be specified in environment variables, configuration files, and the command line allowing maximum configurability and ease of use for operators and scripters.

smtpmail is a little console-based tool for users who have no local mailserver on their machine. It enables these users to send their mail over a remote SMTP server.

Email::Address::XS implements RFC 5322 parser and formatter of email addresses and groups. Unlike Email::Address, this module does not use regular expressions for parsing but instead is implemented in XS and uses shared code from Dovecot IMAP server.

Nullmailer is a simple replacement MTA for hosts that receive no local mail and only relay mail to a fixed set of smart relays. It's useful for systems such as Web servers that must be able to send email notifications, without having to run a full-blown MTA such as sendmail or qmail.

Nullmailer is designed to be simple to configure, easy to extend, and secure. It requires little ongoing administration. The included sendmail emulator front-end should allow most (if not all) sendmail-compatible programs to run without any changes.

ripMIME is a small program to extract the attached files out of a MIME-encoded email package.

The l2md command line tool imports public-inbox archives via Git and exports them in maildir format or to an MDA through a pipe.