MacOS email clients

free and open source email client and personal information manager

web browser with built-in email client

rapid application development platform

email client included by Apple for macOS, iOS, iPadOS and watchOS

text-based email client for Unix-like systems

defunct email client

email and newsgroups client

email client

email client and personal information manager

Sylpheed is an open-source e-mail client and news client licensed under GNU GPL-2.0-or-later with the library part LibSylph under GNU LGPL-2.1-or-later. It provides easy configuration and an abundance of features. It stores mail in the MH Message Handling System. Sylpheed runs on Unix-like systems such as Linux or BSD, and it is also usable on Windows. It uses GTK+.

GroupWise is a messaging and collaboration platform from OpenText that supports email, calendaring, personal information management, instant messaging, and document management. The GroupWise platform consists of desktop client software, which is available for Windows, (formerly Mac OS X, and Linux), and the server software, which is supported on Windows Server and Linux.

Gnus (), or Gnus Network User Services, is a message reader which is part of GNU Emacs. It supports reading and composing both e-mail and news and can also act as an RSS reader, web processor, and directory browser for both local and remote filesystems.

GNUMail is a free and open-source, cross-platform e-mail client based on GNUstep or Cocoa. It is the official mail client of GNUstep and is also used in Étoilé. It was inspired by NeXTMail (NeXT's Mail.app), the predecessor of Apple Mail. GNUMail is based on the mail handling framework Pantomime. GNUMail demonstrated that it is possible to develop cross platform programs for GNUstep and Cocoa.

defunct freeware email management application