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Test Pilot for Thunderbird

Add-on has now been discontinued, see below.

Rated 1 out of 5 stars (15)
27,743 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 (77)
26,993 users

Thunderbird Conversations

This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.

Rated 4 out of 5 stars (434)
25,028 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)
24,800 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 (13)
24,509 users

Display Mail User Agent Requires Restart

Displays icon for user agent of received mails.

Rated 4 out of 5 stars (111)
24,127 users

Confirm-Address Requires Restart

Confirm E-mail address before sending mail

Rated 4 out of 5 stars (52)
22,656 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 (125)
21,670 users

ExQuilla for Microsoft Exchange Requires Restart

Thunderbird email accounts connecting to Microsoft Exchange Web Services.

Rated 3 out of 5 stars (115)
21,429 users

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.

Rated 5 out of 5 stars (73)
20,754 users

SmartTemplate4 Requires Restart

SmartTemplate4 offers an easy way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every account as well as for the default (all email accounts). Also supports the Stationery Add-on.

Rated 5 out of 5 stars (54)
19,278 users

LightningButton Requires Restart

Toolbar-Buttons for Lightning; advances the feature to get rid of the tabbar.

Rated 4 out of 5 stars (16)
17,267 users

Auto Resize Image Requires Restart

Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).

Rated 4 out of 5 stars (33)
16,651 users

Check and Send Requires Restart

Check the message contents and addresses before you send the message...

Rated 4 out of 5 stars (31)
16,628 users

Flex Confirm Mail Requires Restart

Confirm mail address and attachments based on flexible rules.

Rated 3 out of 5 stars (5)
16,513 users

StartupMaster

Asks for the master password at startup (fixes multiple password prompt)

Rated 4 out of 5 stars (277)
16,335 users

TbSync

TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.

Rated 5 out of 5 stars (47)
16,127 users

MinimizeToTray revived Requires Restart

Minimizes windows into the system tray.

Rated 4 out of 5 stars (391)
15,653 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)
15,417 users

Theme Font & Size Changer (fixed)

Fixed version (no 90 day timer till silent failure) of the popular "Theme Font & Size Changer for Thunderbird" addon

Rated 4 out of 5 stars (30)
15,306 users