Most Popular Extensions

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ImportExportTools Requires Restart

Adds some tools to import and export folders and messages

Rated 4 out of 5 stars (235)
46,403 users

Mail Redirect Requires Restart

Allow to redirect (a.k.a. "remail") mail messages to other recipients.

Rated 4 out of 5 stars (132)
31,960 users

DOM Inspector Requires Restart

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.

Rated 5 out of 5 stars (78)
28,153 users

ChatZilla Requires Restart

A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.

Rated 4 out of 5 stars (150)
27,098 users

LookOut Requires Restart

LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).

Rated 4 out of 5 stars (157)
10,799 users

JavaScript Debugger Requires Restart

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

Rated 4 out of 5 stars (52)
8,543 users

MinimizeToTray revived Requires Restart

Minimizes windows into the system tray.

Rated 4 out of 5 stars (395)
6,809 users

FireTray Requires Restart

A system tray extension for Linux and Windows, allowing to set up custom icon, hiding to tray instead of closing, display the number of unread messages in mailing applications, and other features ...

Rated 4 out of 5 stars (287)
5,187 users

MinimizeToTray Reanimated Requires Restart

MinimizeToTray Reanimated is an application mainly dedicated to Thunderbird to allow its minimization in the systray in one click. It is the update of MinimizeToTray Revived, which is not maintained anymore since the recent versions of Thunderbird.

Rated 4 out of 5 stars (138)
3,274 users

Display Mail User Agent Requires Restart

Displays icon for user agent of received mails.

Rated 4 out of 5 stars (112)
3,037 users

Join-NG Requires Restart

Join partial messages. Somewhat similar to MS Outlook Express "combine and decode".

Rated 5 out of 5 stars (5)
2,240 users

Highlighter Requires Restart

Quickly highlight some text in Thunderbird message composing windows.

Rated 4 out of 5 stars (95)
1,824 users

Toolbar Buttons

Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.

Rated 4 out of 5 stars (371)
1,644 users

FlashGot Mass Downloader Requires Restart Featured

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

Rated 5 out of 5 stars (890)
1,642 users

ThunderBirthDay Requires Restart

Display birthdays from the Thunderbird addressbooks as events in Lightning.

Rated 4 out of 5 stars (94)
1,593 users

Awesome Auto Archive

Automatically do Archive/Copy/Delete/Move actions based on user defined rules

Rated 4 out of 5 stars (46)
1,450 users

True Full Screen in SeaMonkey

This extension enables true full screen mode in SeaMonkey for HTML5 video players, slide-shows, etc. and also for full screen invoked manually with the F11 key.

Rated 5 out of 5 stars (17)
1,442 users

Folderpane Tools Requires Restart

Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.

Rated 3 out of 5 stars (124)
1,354 users

Simple Locale Switcher Requires Restart

An easier management of the user interface language

Rated 5 out of 5 stars (14)
1,278 users

Dorando keyconfig Requires Restart

A modified Dorando's addon to rebind keyboard shortcuts. It is designed to be a drop-in replacement, keeping your old settings. (See details for upgrade instructions.)

As of version 2016.2, Custom keys (using custom JavaScript) work again!

Rated 5 out of 5 stars (64)
1,266 users