This is an address lookup tool using a Notmuch database, useful for email address completion.

The sendgmail command provides a minimal sendmail-compatible front-end that connects to Gmail using OAuth2. It is specifically designed for use with git send-email. The command needs a Gmail API key to function.

Guix's version of sendgmail has been patched for compatibility with all known forks, including support for non-@gmail.com email addresses.

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

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

This package provides a TNEF stream reader library and related tools to process winmail.dat files.

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

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.

nmail is an easily configurable terminal-based email client with a ncurses user interface similar to alpine and pine.

Postorius is a Django app which provides a web user interface to access GNU Mailman.

Mail::DKIM is a Perl module that implements the DKIM standard, and the older Yahoo! DomainKeys standard, both of which sign and verify emails using digital signatures and DNS records. Mail-DKIM can be used by any Perl program that wants to provide support for DKIM and/or DomainKeys.

Email::Sender replaces the old and sometimes problematic Email::Send library.

alterMIME is a small program which is used to alter your mime-encoded mailpack. What can alterMIME do?

1. Insert disclaimers,

2. insert arbitrary X-headers,

3. modify existing headers,

4. remove attachments based on filename or content-type,

5. replace attachments based on filename.

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Stalwart is an mail and collaboration server with JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV support and a wide range of modern features.

Alpine is a text-based mail and news client. Alpine includes several tools and applications:

1. alpine, the Alpine mailer

2. pico, the standalone text editor, GNU nano's predecessor

3. pilot, the standalone file system navigator

This package takes your 48x48x1 portrait image and compresses it.

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.

Mailman3 allows emails sent to its mailing lists to be archived by any software provided that there is a plugin (loadable by Mailman3) designed to communicate with it properly. This module contains a Mailman3 archiver plugin which sends emails to HyperKitty, the official Mailman3 web archiver.

Fetchmail is a full-featured, robust, well-documented remote-mail retrieval and forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections). It supports every remote-mail protocol now in use on the Internet: POP2, POP3, RPOP, APOP, KPOP, all flavors of IMAP, ETRN, and ODMR. It can even support IPv6 and IPSEC.

Fetchmail retrieves mail from remote mail servers and forwards it via SMTP, so it can then be read by normal mail user agents such as mutt, elm or BSD Mail. It allows all your system MTA's filtering, forwarding, and aliasing facilities to work just as they would on normal mail.

Alot is a terminal-based mail user agent based on the Notmuch mail indexer. It is written in Python using the urwid toolkit and features a modular and command prompt driven interface to provide a full mail user agent (MUA) experience as an alternative to the Emacs mode shipped with Notmuch.

Blists is a web interface to mailing list archives that works off indexed mbox files. There are two programs: bindex and bit. bindex generates or updates the index file (incremental updates are supported). bit is a CGI/SSI program that generates web pages on the fly. Both programs are written in C and are very fast.

A third-party, open-source ProtonMail bridge. It is designed to run on a server. It supports CardDAV, IMAP and SMTP.

The mblaze message system is a set of Unix utilities for processing and interacting with mail messages which are stored in maildir folders.

Its design is roughly inspired by MH, the RAND Message Handling System, but it is a complete implementation from scratch.

mblaze is a classic command line MUA and has no features for receiving or transferring messages; you can operate on messages in a local maildir spool, or fetch your messages using fdm(1), getmail(1), offlineimap(1), or similar utilities, and send it using dma(8), msmtp(1), sendmail(8), as provided by OpenSMTPD, Postfix, or similar.

mblaze operates directly on maildir folders and doesn't use its own caches or databases. There is no setup needed for many uses. All utilities have been written with performance in mind. Enumeration of all messages in a maildir is avoided unless necessary, and then optimized to limit syscalls. Parsing message metadata is optimized to limit I/O requests. Initial operations on a large maildir may feel slow, but as soon as they are in the file system cache, everything is blazingly fast. The utilities are written to be memory efficient (i.e. not wasteful), but whole messages are assumed to fit into RAM easily (one at a time).

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

public-inbox implements the sharing of an email inbox via Git to complement or replace traditional mailing lists. Readers may read via NNTP, IMAP, Atom feeds or HTML archives.