Most Popular Extensions
TbSync Requires Restart Featured
TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.
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.
Allows you to use your Exchange email accounts that use Outlook Web Access (OWA) with Thunderbird
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!
QuickFolders (Tabbed Folders) Requires Restart Featured
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!
ThunderPEC Requires Restart
ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.
Thunderbird Conversations Requires Restart
This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.
XNote++ Requires Restart
Persistent sticky notes for Thunderbird associated to mails.
This is a port to Thunderbird >= 3 based on XNote 2.1.0 ( https://addons.mozilla.org/en-US/thunderbird/addon/3093 ) with bugfixes and additional features.
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.
Flex Confirm Mail Requires Restart
Confirm mail address and attachments based on flexible rules.
Adds the Google Calendar web interface in a new Thunderbird tab. Creating and viewing events works like in a browser (Firefox, Chrome, ...)
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.
Check and Send Requires Restart
Check the message contents and addresses before you send the message...
Add-on has now been discontinued, see below.
Fixed version (no 90 day timer till silent failure) of the popular "Theme Font & Size Changer for Thunderbird" addon
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).
Display Mail User Agent Requires Restart
Displays icon for user agent of received mails.
Provider for Exchange ActiveSync Requires Restart
Add sync support for Exchange ActiveSync (EAS v2.5 & v14.0) accounts to TbSync
LightningButton Requires Restart
Toolbar-Buttons for Lightning; advances the feature to get rid of the tabbar.
ExQuilla for Exchange Requires Restart Featured
Thunderbird email accounts connecting to Microsoft Exchange Web Services.