Welcome to the FossaMail homepage!
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 (and therefore not affiliated with the Mozilla Corporation).
It is an alternative version of the Mozilla Thunderbird
mail&news client, and based on the Pale Moon browser core.
- Is built from source with compiler optimizations geared
an as stable and smooth operation of the client as possible (Pale
the Pale Moon browser core as its back-end. The client is therefore
based on Pale Moon rather than other Mozilla-derived mail clients.
- Uses its own profile folder on your system. This means it
not interfere with existing Thunderbird installations.
The default profile location is %APPDATA%\FossaMail
- Should be compatible with all Thunderbird (v24/25b era)
add-ons and plugins.
- Is available in 32-bit (x86) and 64-bit (x64) versions for
both Windows and Linux.
with an optional calendar/organizer add-on (Lightning, available from
the download location below) that will allow
it to be used in a Microsoft Outlook style information manager fashion.
- Operating system either:
- Windows Vista or above (Windows XP is not supported), OR
- A recent Linux distribution (it will not run on
particularly old kernel/libc combinations)
- A processor with SSE2 support
- Sufficient hard drive space to install and store your
- An internet connection ;-)
Current version: 25.1.7
Both the program (32-bit and 64-bit) and the lightning add-on are
available from FOSSHub:
Support for FossaMail is provided by the Pale Moon community. You can
discuss bugs, give
feedback and ask for support on the Pale Moon forum. You may also
want to check out the Mozilla help pages for Thunderbird for general use
questions, considering its functionality and feature set being
The source code is available on GitHub:
Mozilla Thunderbird and Mozilla are registered trademarks of the Mozilla
Site and contents ©
2014-2015 Moonchild Productions - All rights reserved
FossaMail is released under the Mozilla Public License (MPL) 2.0