Most Popular Extensions
Display Quota Requires Restart
This extension will display the current status of your IMAP quota in thunderbird's statusbar and will warn you when you reach a configurable limit...
Reinstates the extensions.checkCompatibility preference without respect to the current application version.
Stationery Requires Restart
Extension to mimic Outlook Express Stationery.
Allow you to use HTML files as templates for mail. Also allow custom template in replies or forwarded mail!
'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!
This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.
Copy Plain Text 2 Requires Restart
Copies text without formatting
Simple Locale Switcher Requires Restart
An easier management of the user interface language
Display Mail User Agent Requires Restart
Displays icon for user agent of received mails.
Color Folders Requires Restart
Color your Folder Treeview Icons!
Confirm-Address Requires Restart
Confirm E-mail address before sending mail
"Restart" menu and button, with configurable shortcut key.
Firefox and Thunderbird extension to manage user preferences and user profile CA certificates using group policy
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.
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.
ProfileSwitcher Requires Restart
It adds some options to launch easily other profiles and the Profile Manager.
Folderpane Tools Requires Restart
Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.
QuickNote Requires Restart
A simple note-taking extension.
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.
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!