Most Popular Extensions

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Simple Locale Switcher Requires Restart

An easier management of the user interface language

Rated 5 out of 5 stars (12)
30,853 users

Classic Toolbar Buttons

'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions.

Beta builds on versions page!

Rated 5 out of 5 stars (132)
30,045 users

GPO support For Firefox and Thunderbird

Firefox and Thunderbird extension to manage user preferences and user profile CA certificates using group policy

Rated 4 out of 5 stars (12)
30,012 users

Color Folders Requires Restart

Color your Folder Treeview Icons!

Rated 4 out of 5 stars (122)
29,306 users

Display Mail User Agent Requires Restart

Displays icon for user agent of received mails.

Rated 4 out of 5 stars (104)
28,977 users

Font Finder Requires Restart

FontFinder is created for designers, developers and typographers. It allows a user to analyze the font information of any element on a page, copy any piece(s) of that information to the clipboard, and perform inline replacements to test new layouts.

Rated 4 out of 5 stars (75)
27,890 users

Confirm-Address Requires Restart

Confirm E-mail address before sending mail

Rated 4 out of 5 stars (48)
26,784 users

Lightning Calendar Tabs Requires Restart

Displays tabs which allows quick navigation between time periods in Lightning calendar. All views of calendar are supported. Color of tab texts can be adjusted.

Rated 4 out of 5 stars (8)
26,679 users

Restart

"Restart" menu and button, with configurable shortcut key.

Rated 5 out of 5 stars (90)
26,448 users

Tiny JavaScript Debugger Requires Restart

TinyJSD is a JavaScript debugger for privileged code running Mozilla products like Firefox, Thunderbird, SeaMonkey. It serves to debug the application as well as extensions written in JavaScript.

Rated 4 out of 5 stars (8)
25,874 users

ProfileSwitcher Requires Restart

It adds some options to launch easily other profiles and the Profile Manager.

Rated 4 out of 5 stars (91)
25,018 users

ShowIP Requires Restart

Show the IP address of the current page in the status bar. It also allows querying custom information services by IP (right click) and see location and avaiable vouchers for shopping sites. Additionally you can copy the IP address to the clipboard.

Rated 3 out of 5 stars (278)
24,512 users

Folderpane Tools Requires Restart

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

Rated 4 out of 5 stars (122)
24,331 users

QuickNote Requires Restart

A simple note-taking extension.

Rated 5 out of 5 stars (174)
23,761 users

ThunderPEC Requires Restart

ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.

Rated 5 out of 5 stars (11)
22,051 users

Minimize On Start and Close Requires Restart

A remake of the MinimizeToTray-extension made to fit the Windows 7 taskbar. Instead of minimize the window to the tray it minimize it to the taskbar. It can minimize on startup, when the window is closed and/or when the esc key is pressed.

Rated 4 out of 5 stars (104)
21,869 users

QuickFolders (Tabbed Folders) Requires Restart

The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.

See new mail at a glance after automatic filtering - supports quickFilters addon!

Rated 5 out of 5 stars (117)
21,362 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 (334)
21,244 users

AutoProxy Requires Restart

Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.

Rated 4 out of 5 stars (384)
21,224 users

Thunderbird Message Filter Import/Export Enhanced Requires Restart

Thunderbird Message Filter Import/Export Enhanced is a compatibility port of Wind Li's add on.
Original add on here: https://addons.mozilla.org/en-US/thunderbird/addon/thunderbird-message-filter-imp/

Rated 3 out of 5 stars (48)
20,969 users