Web-browser, advanced e-mail, newsgroup and feed client, IRC chat, and HTML editing made simple—all your Internet needs in one application.
The SeaMonkey® Project
The SeaMonkey project is a community effort to develop the SeaMonkey Internet Application Suite (see below). Such a software suite was previously made popular by Netscape and Mozilla, and the SeaMonkey project continues to develop and deliver high-quality updates to this concept. Containing an Internet browser, email & newsgroup client with an included web feed reader, HTML editor, IRC chat and web development tools, SeaMonkey is sure to appeal to advanced users, web developers and corporate users.
Under the hood, SeaMonkey uses much of the same Mozilla Firefox source code which powers such products as Thunderbird. Legal backing is provided by the SeaMonkey Association (SeaMonkey e.V.).
May 4, 2022
SeaMonkey 2.53.12 released
The SeaMonkey project is proud to present SeaMonkey 2.53.12: The new release of the all-in-one Internet suite is available for download now! 2.53.12 is an incremental update from the 2.53.x branch and incorporates a number of changes as well as fixes from the underlying platform code. NPAPI plugin support has been removed and also has support for building with clang 4 and gcc 6. Additional important security fixes up to the current Firefox / Thunderbird 91.9 ESR are included too. Read the full Release Notes for further information.
If you are upgrading from a 2.49.5 or older release we strongly advise you to make a full backup of your profile before installing the new version.
SeaMonkey 2.53.12 is available in 23 languages, for Windows, macOS x64 and Linux.
Automatic upgrades from previous 2.53.x versions are enabled for this
release, but if you have problems with it upgrading or you need to upgrade from
a version earlier than 2.53.5, please download the full installer from the
downloads section and install SeaMonkey 2.53.12 manually over the previous
For a more complete list of major changes in SeaMonkey 2.53.12, see the What's New in SeaMonkey 2.53.12 section of the Release Notes, which also contain a list of known issues and answers to frequently asked questions. For a more general overview of the SeaMonkey project (and screen shots!), visit www.seamonkey-project.org.
We encourage users to get involved in discussing and reporting problems as well as further improving the product.
April 23, 2022
SeaMonkey 2.53.12 Beta 1 released
SeaMonkey 2.53.12 Beta 1 is now available for free download on the SeaMonkey website.
2.53.12 will be an incremental update on the 2.53.x branch and incorporates a number of enhancements, changes and fixes to the application as well as those from the underlying platform code. NPAPI plugin support has been removed, as also has support for building with clang 4 and gcc 6. Before installing it make a full backup of your profile and thoroughly read and follow the Release Notes. We encourage testers to get involved in discussing and reporting problems as well as further improving the product.
SeaMonkey 2.53.12 Beta 1 is available in 23 languages, for Windows, macOS x64 and Linux.
The SeaMonkey Internet Application Suite
SeaMonkey has inherited the successful all-in-one concept of the original Netscape Communicator and continues that product line based on the modern, cross-platform architecture provided by the Mozilla project.
- The Internet browser at the core of the SeaMonkey Internet Application Suite uses the same rendering engine and application platform as Mozilla Firefox, with popular features like tabbed browsing, feed detection, popup blocking, smart location bar, find as you type and a lot of other functionality for a smooth web experience.
- SeaMonkey's Mail and Newsgroups client shares lots of code with Thunderbird and features adaptive Junk mail filtering, tags and mail views, web feeds reading, tabbed messaging, multiple accounts, S/MIME, address books with LDAP support and is ready for both private and corporate use.
- Additional components include an easy-to-use HTML Editor, the ChatZilla IRC chat application and web development tools like a DOM Inspector.
- If that's still not enough, SeaMonkey can be extended with numerous Add-Ons that provide additional functionality and customization for a complete Internet experience.