Alternatives to Thunderbird for all platforms with Open Source License

  • 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...

    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...

    Open Source Mac Windows Linux BSD

  • Evolution icon

    Evolution

    Evolution is the official personal information manager and workgroup information management tool for GNOME. It combines e-mail...

    Open Source Linux BSD GNOME

  • N1 icon

    N1

    N1 is an email client designed to be friendly and easy to use but also powerful and highly extensible. It works "out of the...

    Open Source Mac Windows Linux

  • Geary icon

    Geary

    Geary is a lightweight email program designed around conversations and built for the GNOME...

    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...

    Open Source Windows Linux BSD Xfce

  • 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...

    Open Source Mac Windows Linux BSD

  • 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...

    Open Source Mac Windows Linux Xfce

  • Trojitá icon

    Trojitá

    Trojitá, is a fast Qt IMAP e-mail client that respects open standards and facilitates modern technologies. Trojitá values...

    Open Source Windows Linux

  • FossaMail icon

    FossaMail

    FossaMail is an Open Source, Mozilla Thunderbird -based mail, news and chat client for Windows and Linux, brought to you by...

    Open Source Windows Linux

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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...

    Open Source 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...

    Open Source Mac Windows Linux BSD

  • nPOPuk icon

    nPOPuk Discontinued

    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

  • Columba icon

    Columba Discontinued

    Columba is an email client written in Java, featuring a user-friendly graphical interface with wizards and internalionalization...

    Open Source Mac Windows Linux BSD

  • 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...

    Open Source Mac Linux BSD

  • Mulberry icon

    Mulberry Discontinued

    Mulberry is a powerful, easy to use electronic mail (email) and calendar program that allows you to send, access, and manage email and...

    Open Source Mac Windows Linux

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  • 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