Alternatives to Thunderbird for all platforms with Open Source License

Platforms

Mobile

Indie / Classic

Show 4 hidden platforms
  • K-9 Mail icon

    K-9 Mail

    K-9 is an open source email client for Android with multi-folder sync, email signatures, Bcc-to-self, return-address configuration, keyboard shortcuts, Exchange Support, message flagging, IMAP deletes, saving attachments, configurable...

    Open Source Android Android Tablet

  • SeaMonkey icon

    SeaMonkey

    The SeaMonkey project is a community effort to develop the SeaMonkey all-in-one internet application suite. RAM-demand similar to Mozilla Firefox . Such a software suite was previously made popular by...

    Open Source Mac Windows Linux BSD PortableApps.com

  • Evolution icon

    Evolution

    Evolution is the official personal information manager and workgroup information management tool for GNOME. It combines e-mail, calendar, address book, and task list management functions. It has been an official part of GNOME since...

    Open Source Linux BSD GNOME

  • Geary icon

    Geary

    Geary is an email application built for GNOME 3. It allows you to read and send email with a simple, modern interface.

    Open Source Linux BSD GNOME

  • Claws Mail icon

    Claws Mail

    Claws Mail is an email client (and news reader), based on GTK+, featuring Quick response Graceful, and sophisticated interface Easy configuration, intuitive operation Abundant features Extensibility ...

    Open Source Windows Linux BSD Xfce

    • Small and quick and not flooded with choices! Guest • Jun 2016 Disagree   Agree
  • Sylpheed icon

    Sylpheed

    Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client (mailer, MUA). Sylpheed runs on many systems such as Windows, Linux, BSD, Mac OS X and other Unix-like systems. Sylpheed uses GTK+ GUI toolkit. The...

    Open Source Mac Windows Linux BSD PortableApps.com

  • Mutt icon

    Mutt

    Mutt is a small but very powerful text-based mail client for Unix operating systems. Some of its features are: color support, message threading, MIME support (including RFC2047 support for encoded headers), PGP/MIME (RFC2015), various...

    Open Source Mac Windows Linux Xfce

  • FossaMail icon

    FossaMail

    FossaMail is an Open Source, Mozilla Thunderbird -based mail, news and chat client for Windows and Linux, brought to you by the Pale Moon developers. FossaMail: Is built from source with compiler optimizations...

    Open Source Windows Linux

  • Trojitá icon

    Trojitá

    Trojitá, is a fast Qt IMAP e-mail client that respects open standards and facilitates modern technologies. Trojitá values vendor-neutrality that IMAP provides and is committed to be as interoperable as possible.

    Open Source Windows Linux

  • Kontact - KMail icon

    Kontact - KMail

    KMail is the email component of Kontact, the integrated personal information manager of KDE. Kontact is a personal information manager and groupware software suite for KDE. It supports calendars, contacts, notes, to-do lists, news...

    Open Source Mac Windows Linux BSD

  • Pantheon Mail icon

    Pantheon Mail

    Pantheon Mail is a free open source email client forked by the elementary OS community from Geary . Features Modern and straightforward interface ...

    Open Source Linux elementary OS

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  • sup icon

    sup

    Sup is a console-based email client for people with a lot of email. It supports tagging, very fast full-text search, automatic contact- list management, custom code insertion via a hook system, and more. If you're the type of...

    Open Source Linux

  • mu icon

    mu

    mu is a tool for dealing with e-mail messages stored in the Maildir-format, on Unix-like systems. mu's main purpose is to help you to find the messages you need, quickly; in addition, it allows you to view messages, extract...

    Open Source Mac Linux BSD

  • Mulberry icon

    Mulberry

    Mulberry is a powerful, easy to use electronic mail (email) and calendar program that allows you to send, access, and manage email and calendars. Mulberry also helps you manage other related information, such as contact information. ...

    Open Source Mac Windows Linux

    • Discontinued The project is no longer developed. Last version, 4.0.8, released in February 2007, can be still downloaded from the official website.
  • Balsa icon

    Balsa

    Balsa is an e-mail client for GNOME, highly configurable and incorporating all the features you would expect in a robust mail client.

    Open Source Linux Xfce

  • Columba icon

    Columba

    Columba is an email client written in Java, featuring a user-friendly graphical interface with wizards and internalionalization support. Its a powerful mail management tool with features to enhance your productivity and communication.

    Open Source Mac Windows Linux BSD

    • Discontinued The project is no longer developed. Last version, 1.4, released in March 2007, can be still downloaded from SourceForge.
  • nPOPuk icon

    nPOPuk

    nPOPuk is an ultra-small, but comprehensive, e-mail client that runs on a wide range of Windows-based operating systems

    Open Source Windows Windows Mobile

    • Discontinued The project seems to be no longer updated. Last version, 3.03, released in October 2014, can be still downloaded from the official website.
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